[go: up one dir, main page]

WO2003099729A1 - Procede d'extraction de metaux lourds et solides par formation d'un complexe de polyelectrolytes biodegradables (pectine et quitosan) - Google Patents

Procede d'extraction de metaux lourds et solides par formation d'un complexe de polyelectrolytes biodegradables (pectine et quitosan) Download PDF

Info

Publication number
WO2003099729A1
WO2003099729A1 PCT/MX2003/000044 MX0300044W WO03099729A1 WO 2003099729 A1 WO2003099729 A1 WO 2003099729A1 MX 0300044 W MX0300044 W MX 0300044W WO 03099729 A1 WO03099729 A1 WO 03099729A1
Authority
WO
WIPO (PCT)
Prior art keywords
removal
chitosan
solids
heavy metals
solution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/MX2003/000044
Other languages
English (en)
Spanish (es)
Inventor
Katiushka AREVALO NIÑO
Luis J. GÁLAN WONG
Carlos Eduardo Hernandez Luna
Ruby Yarisol Salazar Alpuche
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Universidad Autonoma de Nuevo Leon
Original Assignee
Universidad Autonoma de Nuevo Leon
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Universidad Autonoma de Nuevo Leon filed Critical Universidad Autonoma de Nuevo Leon
Priority to AU2003230443A priority Critical patent/AU2003230443A1/en
Publication of WO2003099729A1 publication Critical patent/WO2003099729A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5263—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using natural chemical compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds

Definitions

  • This invention describes a new process for the removal of heavy and solid metals, through the use of biodegradable polyelectrolytes such as pectin and chitosan, which act in synergy for complexing and removal of metals and solids in various processes.
  • Biodegradable polymers are those products that contain materials that facilitate and enhance photo and biodegradation processes. Biodegradation is the breaking of materials by the action of living organisms. For the biodegradation of polymers, the most important organisms are fungal and actinomycete bacteria (Maddever & Chapman, 1989).
  • Biodegradable polymers such as polysaccharides can be obtained from various sources such as microorganisms, plants and animals. Some examples of polysaccharides of microbial origin are dextran and xanthan which are very useful today in the food industry among others; On the other hand, among the polysaccharides whose origin is the plants we find alginic acid, cellulose, starch, pectin, gum arabic etc. There are also natural polymers of animal origin such as heparin, glycogen and chitin.
  • CPE polyelectrolyte or polysal complexes
  • Pectin is a natural polymer of D-galacturonic acid and ac methyl ester.
  • D-galacturonic which is obtained as a byproduct of the industrialization of apple and lemon (Walter, 1991), this polymer can be negatively charged due to the presence of carboxylic groups in its molecular chain. which is considered an anionic polyelectrolyte capable of capturing heavy metals
  • Chitosan is a copolymer that is obtained as a result of the deacetylation of chitin which is obtained from the shell of crab and shrimp.
  • Chitosan is a copolymer of N-acetylglucosarnine and N-glucosamine which gives it the possibility of being positively charged as a cationic polyelectrolyte.
  • CPE Biodegradable Polyelectrolyte Complexes
  • polymer from the Greek polys, "many”, and mere, “parts" to denote the molecular substances of high molecular mass formed by the polymerization (binding) of monomers, molecules of low molecular mass.
  • Polymers like any other organic compound, can have functional groups and chiral carbons. They can form hydrogen bonds and experience dipole-dipole interactions.
  • the chemical composition of a polymer chain is called the primary structure.
  • the arrangement of the chain in relation to itself and other chains, is called secondary structure.
  • This secondary structure can be as important in determining the properties of a polymer as its chemical composition.
  • Polymers can be classified into two large groups according to their origin:
  • Man-made polymers are almost as varied as natural polymers. Currently we wear polyester clothes, we sit on vinyl chairs and write on formic tables, in addition to being able to acquire carpets made of polyester or polypropylene at a lower cost than those made with natural fibers; A large number of things we use and that are indispensable today are made from synthetic polymers.
  • natural polymers can be classified into three categories: l) Proteins (such as silk, muscle fibers and enzymes). 2) Nucleic acids. 3) Polysaccharides (pectin, chitin, chitosan, starch, cellulose, etc.) (Brown et al, 1998) Polysaccharides are formed by the union of many monosaccharides, from 11 to hundreds of thousands. Their links are O-glycosides with loss of a water molecule due to linkage. These polymers can be produced by microorganisms (xanthan and dextran), by plants (alginic acid, gum arabic, cellulose, starch), by mammals and crustaceans (heparin, glycogen, chitin). The most important polysaccharides are starch, glycogen and cellulose, which are made up of repeating glucose units.
  • Polysaccharides also called glucans, differ in nature by their repeated monosaccharide units, the length of their chains and the degree of branching. Therefore, these polymers can be grouped into:
  • Homopolysaccharides constituted by a single type of monomer unit.
  • Heteropolysaccharide This class of polymers are formed by more than one type of monosaccharide.
  • the biological functions of the polysaccharides can be of 2 types: 1. -Energy reserve ( ⁇ -Glucosidic bond). Like starch, glycogen and pectin (plants) 2.-Structural ( ⁇ -Glucosidic bond). Like chitin (insects) and cellulose.
  • Structural polysaccharides essentially serve as structural elements in cell walls and covers, in intercellular spaces and in tissue conjunctive, where they shape and confer elasticity or rigidity to animal and plant tissues, as well as protection and support to single-celled organisms.
  • polysaccharides are found to be the main exoskeleton compounds of many invertebrates.
  • chitin polysaccharide which is a homopolymer of N-acetyl-D-glucosamine, with ⁇ bonds (1-4), is the main organic element in the exoskeleton of insects and crustaceans (Lehninger, 1991).
  • Pectin is a polysaccharide which is present in the cell wall of plant tissues.
  • the pectic substances present in this polysaccharide contribute to the adhesion between the cells and the mechanical strength of the cell wall, behavior presented in the way it stabilizes the gels.
  • Pectin is a linear heteropolymer whose main component of its structure is D-galacturonic acid, which are linked by glycosidic ⁇ (1-4) bonds; This polymer has varying amounts of L-rhamnose, D-galactose, L-arabinose, and occasionally traces of other sugar units. (Fogarty and Ward, 1972).
  • Pectin has about 75% of its carboxyl groups esterified with methanol as observed in the present chemical structure (Whitaker, 1994).
  • Pectin structure is H or CH 3 , with 75% of carboxylic groups esterified with methanol.
  • pectin can be characterized in:
  • pectin has water solubility and insolubility in organic solvents such as formaldehyde.
  • the water solubility of pectin is determined by the number of methoxyl groups, their distribution and molecular weight (PM). Generally the solubility increases with the decrease of the PM and with the increase of methyl ester groups; However, the pH, temperature, type and concentration of salts present play a very important role in solubility. When powdered pectin is added, water tends to hydrate very quickly and remain as a cluster of partially hydrated and suspended particles that are difficult to dissolve; Therefore, pectin needs to be incorporated slowly and with rapid agitation.
  • viscosity is related to the PM and the degree of esterification, concentration, pH and the composition of the solution.
  • pectin has been reported that the addition of monovalent cation salts, such as sodium chloride (NaCl) to pectin solutions causes the viscosity reduction; This effect is more pronounced with PBE solutions.
  • monovalent cation salts such as sodium chloride (NaCl)
  • pectin In order for pectin to remain stable, more or less acidic conditions and normal temperatures are required, because at high temperatures and very acidic conditions it undergoes depolymerization. But if the temperature, pH and reaction time are controlled, it is possible to produce pectic acid because the pectma undergoes a deesterification and only a slight depolymerization. Pectic acid is a pectin in which the largest amount of methoxy groups have been removed.
  • the formation of pectin gels occurs when pectin chains that are originally highly hydrated by water molecules suffer dehydration when water molecules are replaced with solute molecules.
  • the gels that are obtained and the nature of them depend mainly on the degree of polymerization and the degree of methylation. Under similar conditions, the degree of gelation of a pectin gel is generally proportional to PM and is inversely proportional to the degree of esterification (Towle and Christensen, 1980).
  • the main waste material for obtaining pectin today is the citrus peel, preferably 1 a lemon, although grapefruit, lime and orange peel are also used.
  • the shell used to obtain pectin comes from the toy industry.
  • the husk after juice extraction contains 2-4% pectin and in dry form 20-40%.
  • Another important source of pectma is the waste obtained from the apple juice extraction process, which in the same way that citrus peel can be used fresh or dried.
  • the pectin content in dried apple residues is 10-20%.
  • pectin production is related to the areas where citrus and apple are produced and processed. California has a lot of industries pectin producers from citrus. In other countries such as England, France, Germany and Switzerland you get apple pectin.
  • Pectin was initially produced commercially as a liquid extract, currently it is produced as a high purity refined powder. This product has always been considered as a constituent of human food. Pectin is recognized by FAO as a safe additive, which has no restrictions on use if good manufacturing practices are used.
  • Pectin is used mainly in the food industry, for the production of jellies, jams, instant jellies for pastry, drinks, artificial cherries, stabilizer of some dairy products and frozen desserts.
  • pectin has played a very important role.
  • pectin can help lower blood cholesterol levels, it is also used in medications for the treatment of gastric and duodenal ulcers.
  • this polysaccharide we find that when combined with gelatin could be used for the encapsulation of medicinal agents and their release in the body.
  • T al is the case of 1 mixture and worked with pectin-aspirin, which does not cause gastric irritation. (Towle et al, 1980; Fogarty and Ward, 1972).
  • pectin One of the properties of great interest that pectin showed was its ability to trap heavy metals through a complexing mechanism. This is possible because pectin is found as a negatively charged polyelectrolyte and can bind to positively charged heavy metal ions.
  • Affinity that Presents this polyelectrolytes is from greater to lesser proportion for the following metals: Lead (Pb)> Barium (Ba)> Cadmium (Cd)> Strontium (Sr), continues to decrease in its ability to trap alkaline earth ions and alkaline ions.
  • Pectins with a low degree of methylation or esterification are an antidote for heavy metal poisoning, due to an increase in stool excretion and a decrease in reabsorption.
  • heavy metals have been reported with urinary excretion.
  • oligogalacturonides which occur when the pectin is degraded by microorganisms in the colon and with resorption in the body. These oligogalacturonides catalyze the excretion reaction as well as their binding to heavy metals, resulting in urinary excretion. The way in which this occurs has not been clearly understood.
  • Medetopekt which is a tablet consisting of low-methylation apple pectin with an improved ability to bind heavy metals, especially lead, it also contains apple powder and fiber thereof, etc (Endress, 1998).
  • Chitin is the second most abundant polymer in nature after cellulose and is the largest polysaccharide in insect exoskeletons, fungal cell wall and shell of crustaceans, this polysaccharide is made up of ⁇ (l-4) bonds linked to repeated units of N-acetylglucosamine (icol, 1991; Xu et al, 1996; Dinesh et al, 2000).
  • Chitin is obtained from the industrialization of the crab and shrimp shell, and is presented as a crystalline or amorphous powder insoluble in water, organic solvents, diluted acids or alkalis. It dissolves in concentrated mineral acids with the simultaneous degradation of the polymer (Mathur, NK and Narang, CK 1990). Chitin is a widely used unbiopolymer in the food industry, agriculture, medicine, biotechnology, etc. An important derivative of chitin deacetylation is chitosan, this product was discovered in 1859 by Professor C. Ruget (Hennen, 1996).
  • Chitosan with its available amino group.
  • Chitosan is an amino-polysaccharide derived from chitin, which is deacetylated when subjected to a hydrolysis treatment with NaOH, subsequently rinsed, the pH is adjusted, decanted and finally this polymer is subjected to a drying treatment in which is obtained in the form of flakes and later the chitosan powder.
  • glucosamine units present in chitosan contain a free amino group, which can take a positive charge that provides amazing properties (Hennen, 1996).
  • Chitosan is a polymer of high molecular weight, natural, non-toxic, biodegradable, widely produced and marketed in North America. (Sanford, P; 1989).
  • Chitosan [ ⁇ - (l— »4) -2-amino-2-deoxy-D-glucose] is generally considered and presented as a homopolymer, however the deacetylation process is rarely complete, so the product obtained is a copolymer containing 2- acetoamido-2deoxy- ⁇ -D-glucopyranose and residues of 2-amino-2-deoxy- ⁇ -D-glucopyranose.
  • chitosan can be characterized based on its GD in:
  • the solubility depends on the distribution of the amino and N-acetyl groups.
  • chitosan is a linear cationic polyelectrolyte at acidic pH and with a high charge density, one charge per unit of glucosamine.
  • Some materials with negative charges proteins, ammonium polysaccharides, nucleic acids, etc. interact with the chitosan in acidic aqueous solutions and react, obtaining an electrical neutrality and a Polyelectrolyte Complex.
  • cationic properties of chitosan is its excellent capacity as a flocculant due to the large number of -NH 3 groups that can interact with negatively charged colloids.
  • metals such as: Iron (Fe), Copper (Cu), Cadmium (Cd), Mercury (Hg), Lead (Pb), Chromium (Cr), Nickel (Ni), Uranium (U), etc.
  • Chitosan forms very viscous solutions in acetic acid and formic acid which can be used to make membranes. (Sanford, 1989) Biological Properties
  • Chitosan has biocompatibility properties among which is that it is a non-toxic, biodegradable and natural polymer. Within its bioactivity, chitosan has shown the ability to facilitate wound healing, and it also has the ability to reduce blood cholesterol levels and stimulate the immune system. (Sanford, 1989). Chitosan and chitin have a low degree of toxicity; an LD 50 for chitosan in laboratory mice of 16g / kg body weight, which is close to that of sugar and salt. (Singh et al, 2000).
  • Chitin is a waste product of the food processing industries of the sea, which has approximately 1.45 * 10 5 metric tons on a dry basis of such waste worldwide and 1.2 * 10 5 metric tons of world production of chitin (Knorr, 1991).
  • chitin and chitosan are commonly produced from shrimp and crab from Alaska and Mexico (Muzarelli, 1982).
  • chitin is also produced by fungi such as Mucor rouxii, Aspergillus niger, Aspergillus phoenicis, Histoplasma capsulatum, etc; which annually produce 3.2 * 10 4 metric tons of this product.
  • the total sales of chitin / chitosan are expected in 2 million US dollars in the next 10 years, this is due to the large number of applications (Knorr, 1991). Chitin and chitosan production is based on crab shell and shrimp from industries located in Oregon, Washington, Virginia and Japan. Many countries have sources of untapped crustaceans such as Norway, Mexico and Chile. (Arévalo, 1996).
  • Chitosan is a biopolymer with a large number of applications, being used in the food industry, cosmetics, agriculture, biotechnology, medicine and pharmaceutical industry, water treatment and metal capture. Chitosan in the food industry is used as a precipitation agent of protein material, chitosan should not be present in foods at concentrations greater than 0.1%, this polymer is also used in the fruit juice industry for clarification of these, it is used as a protective cover of fruits, in the recovery of microalgae and purification of drinking water, etc. The use of this biopolymer in drinking water is regulated by the U.S. Enviromental Protection Agency (Sanford, 1989; Knorr, 1991).
  • This polymer of great properties is used as a non-toxic cationic polyelectrolyte in the treatment and care of skin and hair.
  • the transparent solutions of this polymer form films that adhere to the hair and skin, currently this polymer and some modifications thereof, such as N-carboxybutyl chitosan are used to enrich some hair and nail care products: spray, conditioners, shampoo and nail varnishes.
  • the industries that are marketing these products are in Germany, Japan etc. (Sanford, 1989; Nicol, 1991).
  • Chitosan in agriculture has been used by applying it in a 0.4% solution in the form of a spray directly on tomato plants eliminating the infection caused by the tobacco mosaic virus (Muzzarelli, 1982).
  • chitosan is widely used for immobilization of enzymes and cells, preparation of packed columns and biomembranes, etc. (Mathur et al, 1990; Sing et al, 2000).
  • Chitosan has stood out for its multiple uses in the area of medicine and pharmaceutical products, where new applications are discovered every day.
  • a number of products are made from chitosan, among which are:
  • Synthetic skin which is used to treat burns, ulcers, infected skin, etc. (Alian et al, 1984; Mathur et al, 1990; Singh et ⁇ /, 2000).
  • Surgical sutures.- Chitin is also used in them, and a strong fibrous filament is obtained which does not need to be removed after wound healing (Mathur et al, 1990; Dinesh et ⁇ , 2000).
  • Cholesterol reducing agent.- Chitosan is widely used today as part of a diet, to eliminate fat (Sanford, 1989; Knorr, 1991).
  • New products from the medical and pharmaceutical area continue to be developed every day or perfected, using chitosan as the main product.
  • Chitosan is a multifunctional polymer with great properties due to its chemical and molecular structure which gives it various properties, among which is the coagulant / flocculant, adsorbent and chelating agent, which gives the treatment industry utility of waters.
  • the accumulation of heavy metals and pesticides in the environment, has created great damages in the food chains, for which the purification of water contaminated with these toxic substances is required for their discharge and reuse (Knorr, 1991).
  • the use of conventional methods for the removal of metals in waters from the industry such as chemical precipitation or oxidation, filtration, electrochemical treatments, ion exchange, evaporation recovery can be ineffective and expensive (Volesky, 1987).
  • Chitosan is an excellent chelator of harmful metals (copper, nickel, chromium, cadmium, manganese, cobalt, lead, mercury, zinc, uranium and silver) because they have the ability of their amino and hydroxy groups to act as electron donors . This capability has been confirmed with the use of advanced instrumental techniques such as EDAX (Energy Dispersive Analysis of X ray) and ESCA (Electron Spectroscopy for Chemical Analysis) (Muzarelli, 1983; Standford, 1989).
  • chitosan Chemical modifications of chitosan have been carried out, such modifications were for the amino groups and primary hydroxyl groups. Some functional groups such as carboxyl groups, sulphides and phosphors were introduced in chitosan and tested to trap copper, nickel, cobalt, manganese ions, it has also been proven that chitosan not only has a good adsorption capacity, but a high selectivity when found in the presence of several metals. (Mitani et al, 1997; Tan et al, 1998).
  • NCMC N-carboxymethyl chitosan
  • chitin and chitosan polymers lie in part in their biodegradability which is based on the fact that both are naturally occurring polysaccharides. It is considered that there is a great variety of microorganisms in soil and water capable of degrading chitin and chitosan. Some only degrade chitosan while others degrade both polysaccharides. Chitin-degrading microorganisms are extremely common in the soil (10 5 CFU per g of garden soil, forest and agricultural soil samples) (Arévalo, 1996).
  • chitosan is degraded by chitosanase produced by microorganisms such as: Arthrobacter, Bacillus, Streptomyces, Aspergillus and Penicillum, which are widely distributed in the ecosystem.
  • Chitin is degraded by chitinases, which are distributed in nature and in the digestive system of many animals.
  • the bacterium Serratia marcensces and Enterobacter liquefaciens are 10 times more active than Aspergillus fumigatus and Streptomyces.
  • the chitinase produced by Serratia marcensces can be easily purified.
  • Polyelectrolytes this term denotes a class of macromolecular compound, which when dissolved in a convenient polar solvent (usually water), spontaneously acquires or may acquire a large number of elementary charges distributed along the macromolecular chain (Nakajima and Shinoda , 1976). What are polyelectrolytes?
  • the number of elementary charges may be of the same order as the number of monomer units (degree of polymerization). In most cases the polyelectrolyte charges are all of the same sign but there may be polyelectrolytes with both charges or be prepared in the laboratory (Mandel, 1990).
  • Polyelectrolytes are currently of high practical relevance such as: stabilizers, greasing agents, gelling agents, super absorbents, flocculants, membranes of complex polyelectrolytes for separation or microencapsulation processes (Dautzenberg, 2001).
  • Polyelectolites in turn can be classified in different ways: By their nature: Natural macromolecules (DNA) Synthetic macromolecules (acrylic acid) Chemically modified biopolymers (carboxymethyl cellulose)
  • Copolymer Homopolymers Regarding its electrochemical capacity Polycides or Polyanions Polybases or Polyses Polisals (Mandel, 1990).
  • CPEs or polysales are formed when macromolecules of opposite charges are allowed to interact (Nakajima and Shinoda, 1976; Izumrudov et al, 1998).
  • Reaction between an anionic and another cationic polyelectrolyte usually involves a polymeric acid or its salt with a polymeric base or its salt.
  • Coacervate The term coacervate or c orcervation d enot a physical phenomenon that usually occurs in aqueous solutions of highly hydrated polymers; It is defined as the spontaneous separation of a single-phase aqueous solution of a polymer in two different phases, one of which has a relatively high polymer concentration, while the other has a relatively low concentration.
  • the tendency to experience coacervation is a fundamental function, of the molecular size of the polymer and the degree of penetration by water in its interstices (Lehninger, 1991).
  • Gel. -A gel consists of polymer molecules interwoven in entangled form, one could say that it is an interconnected network immersed in a liquid medium. The properties of the gels depend on the complex interaction between a solvent and a solute.
  • the mesh bonds are not an interaction point, but they involve a large number of segments of two or more polymer molecules, usually the binding areas are well defined, which are well stabilized by a combination of weak intermolecular forces. Individually these forces are not sufficient to maintain the integrity of the structure of the junction zones, but together, their effect provides thermodynamic stability to the gels (Walter, 1991).
  • CPEs present electrostatic interactions as the main force of attraction; but hydrogen bonds, dipole forces and hydrophobic interactions often play an important role in determining the final structures. Hydrogen bridges are generally weak bonds, so only when a good number of them cooperates can they confer thermodynamic stability to the gel network.
  • the structure and properties of the CPE's can be studied by means of elementary analyzes such as: solubility and increase of measurements, spectroscopy techniques, electron microscopy, etc. (Smid and Fish, 1990).
  • the CPE's have been observed can be formed in two ways:
  • Non-stoichiometric in a 1: 2 ratio (for each cationic group two ammoniums are joined or vice versa) etc.
  • CPE's for filtration and applications in the medical area as antithrombogens.
  • the formation of CPE with pH-based biopolymers has been investigated with cationic polymers including glycol-chitosan and hyaluronic acid, chondroitin A sulfate, chondroitin C sulfate, heparin or cellulose sulfate as a polyanionic component, it was found that CPE's were developed stoichiometrically, except for chitosan-heparin glycol, all these results were analyzed taking into account the molecular conformation of the chain of polymer components and the distribution of ionizable groups along the chain (Nakajima and Shinoda, 1976; Kikuchi and Fukuda, 1974).
  • CPEs have been obtained with different properties: antithrombogenic agents and blood coagulation agents, were made using modified biopolymers such as Sodium Dextran Sulfate (ammonium polyelectrolyte) and Glycol Chitosan (cationic polyelectrolyte), the latter dissolved in two different acids (Fukuda and Kikuchi, 1976).
  • polyelectrolyte complex has been obtained from Sodium Dextran Sulfate and Dextran containing Diethylaminoethyl groups, these complexes have been studied and chemically evaluated (Kikuchi et al, 1976).
  • CPE's have also been prepared using Glycol-Chitosan as a cationic component and some polysaccharides such as Carboxymethyl Cellulose, polygalacturonic acid, alginic acid and Dextran Sulfate with sodium salts as cationic components evaluating their mixing ratio and obtaining thin films which have been used to measure and evaluate its dielectric properties at different temperatures, as well as electrical conductivity (Srinivasan and Kamalam, 1982).
  • Glycol-Chitosan as a cationic component
  • some polysaccharides such as Carboxymethyl Cellulose, polygalacturonic acid, alginic acid and Dextran Sulfate with sodium salts
  • Polyelectrolyte complexes have been made by mixing solutions of carboxymethyl starch and diethyl ethylamino starch at different mixing reasons. This complex is insoluble in water (Willet, 1995).
  • CTR Deionized water
  • FTIR Fourier Transformed Infrared Spectroscopy
  • the Moisture content of the different polysaccharides was determined by weighing on an analytical balance (Mettler Toledo Model AB2049) 1 g of each of the polysaccharides in a constant weight watch glass, D samples were placed in an oven (Marsa Model HDP-334) at a temperature of 74 ° C for 24 hours (hrs). The clock glass was transferred to a desiccator until it reached room temperature (15 to 30 minutes.) Weigh the container with the dried sample. The experiments were carried out in triplicate for statistical validation.
  • chitosan polyelectrolyte or cationic polymer
  • pectin polyelectrolyte or anionic polymer
  • the volume of titrating agent consumed during the titration was measured and based on its molarity the ionizable groups for pectin (COO " ) and for chitosan (NH 3 ) were determined, in this case it could be determined with PM.
  • the pH value at the midpoint of the titration is numerically equal to the pK value of the acid valued. Equimolar concentrations of the proton donor species (HA) and proton acceptor (A " ) are present at the midpoint.
  • the pK of an acid can actually be calculated, from the pH at any point on the titration curve of the acid, provided that the concentrations of the proton-giving and acceptor species at that point are known Determination of optimal pH of the polymers
  • the optimum pH is the pH at which the greatest amount of ionizable groups is found for each polymer and that value will be given by the maximum point of the titration, which is the one where the titrated agent exhibits a sharp change in pH by a excess of the title agent.
  • the value of pK is found, which is the midpoint of the titration and 50% of ionizable groups are present (Lehninger, 1991).
  • the intrinsic viscosity of the polymers was measured in an Oswald viscometer, held in a temperature bath at 30 +/- 2 ° C in silicone oil (Macossay, 1997)
  • Pectin was dissolved in distilled water at concentrations of 0.25, 0.20, 0.15, 0.10 and 0.05 g per deciliter (di).
  • chitosan was dissolved in a 0.1Molar acetate buffer (M) and aq.
  • Acetic 0.2M prepared in distilled water, accentrations of 0.25, 0.20, 0.15, 0.10 and 0.05 g / di.
  • the viscometer is filled with 10 ml of the specific white solution for each polymer and approximately 5 time measurements (timed) take to pass the solvent from point A to B of the viscometer. Subsequently, the analysis of the polymer solutions is carried out, from 1 to the solution with the lowest concentration to the one with the highest concentration.
  • the reduced viscosity is plotted against viscosity and a linear regression is performed if necessary, then extrapolation of the data is carried out.
  • the polymer concentration g / dl
  • the [D] c "1 In Dr and Dsp / c.
  • K and ⁇ viscometric constants according to the degree of chitosan deacetylation.
  • [D] intrinsic viscosity (ml g) (obtained from extrapolation)
  • the volume of water used to prepare the polymer solutions was 40 ml of deionized H 2 O.
  • the required amount of pectma was weighed to have a solution at 1% concentration in deionized water, the pectma was dissolved in 40 ml of deionized water when subjected to stirring with a magnetic bar on a plate (Corning stirrer / hot piate) of Stirring, the pH of the solution was adjusted in a potentiometer (Beckman Mod ⁇ 63) with solutions of NaOH and HC1 1 and 0.1M according to the formulation to be prepared.
  • the cationic polymer solutions were elaborated differently because the cationic polymer is not soluble in water, whereby 1% volume to volume (v / v) of acetic acid was added to the deionized water and subsequently proceeded to solubilize the Polymer by means of continuous stirring with a magnetic bar on a stir plate (Corning stirrer / hot piate), the pH was also adjusted with NaOH and HC1 solutions 1 and 0.1 M according to the formulation to be prepared.
  • the CPE was obtained by homogeneously mixing the cationic solution with the ammonium. Once the mixture was carried out, stirring was carried out for 15 minutes in a shaker (Lab-line Incubator Shaker Orbit) at 150 revolutions per minute (r.p.m.). The CPE obtained was separated from the supernatant with a spatula and dissection forceps, to then be weighed on a scale (Mettler Toledo PB 3001) and obtain the wet weight of said complex.
  • formulations B and D were selected, from these formulations the use of the cationic polymer was optimized.
  • the reason for such optimization is because the polymer has a higher cost than that of the anionic polymer.
  • the concentrations of the cationic polymer were set with which it was intended to obtain a good formation of the CPE.
  • formulation B Four concentrations were set which were reduced from the order of 1% to 0.25% in a homogeneous manner.
  • formulation B 4 different formulations were also prepared for formulation D.
  • the solutions of the polymers were prepared according to the% concentration required, also the pH was adjusted as mentioned above, and the formulations were prepared with 4 repetitions measuring the same parameters as for the initial formulations (wet and dry weight of the CPE). in order to be able to select the formulation that requires less cationic polymer and that continues to show good performance in terms of CPE formation.
  • the CPE ashes were digested with 7.5 ml of concentrated nitric acid (HNO 3 ) and the entire sample was heated at 100 ° C for 10 minutes or until all the ashes dissolved in the solution.
  • HNO 3 concentrated nitric acid
  • the crucible contents were deposited in a 25 ml volumetric flask and diluted to the mark with double-distilled water, to subsequently analyze the sample in the ICP. These dilutions at 25 ml from the volumes obtained from the samples were made in order to provide a measurement within the ranges established by the spectrophotometer.
  • the supernatant because it presented CPE residues that could not be eliminated, was filtered using a bushner funnel, a kitazato flask, a vacuum pump and a No.l filter paper, in order to eliminate CPE residues that could interfere with the measurement of metals; the solutions once free of organic waste were analyzed in the plasma emission spectophotometer. The filtered solutions did not need to be diluted because concentrations were expected within the operating ranges of the plasma emission spectrophotometer.
  • the cationic and anionic polyelectrolyte solutions of the formulations B2, B3, D2, D3 with known concentration and pH were prepared, dissolving the polymer in deionized water and adjusting the pH with a solution of NaOH or HC1 1 and 0.1 M.
  • the solutions of the polyelectrolytes were prepared and the volume of the 3 samples was measured, they were mixed by placing the problem sample (in this case the 50 ml of mud) in a flask and first adding the polyelectrolyte with a pH closer to the sample, to subsequently add the remaining polyelectrolyte.
  • the problem sample in this case the 50 ml of mud
  • the flasks were then introduced into a shaker (Lab-line Incubator Shaker Orbit) with stirring for 15 minutes and 150 rpm, the shaker flasks were removed and the solids retention was separated.
  • a shaker Lab-line Incubator Shaker Orbit
  • microorganism used in this work was: a strain of Serratia marscensens provided by the Laboratory of Basic Bacteriology of the Department of Microbiology and Immunology of the Faculty of Biological Sciences of the U.A: N.L Maintenance of the strain
  • strains were activated in nutrient broth and maintained by periodic reseeding in tubes with nutrient agar, pH 7.0 under refrigeration
  • the dilutions were carried out in tubes to be able to read in the Klett-Summerson Photocolorimeter.
  • the standards were introduced every two hours in the photocolorimeter and the measurement of the growing cells in the nephelometric flasks was carried out, until the desired cell / ml number was obtained.
  • the CPE which was recovered from 4 flasks with the help of a clamp, was weighed on an analytical balance and taken to dry in a laminar flow hood for a period of time, once the excess liquid was removed, the excess liquid was removed. despite new in an analytical balance to obtain the final weight.
  • the percentage of weight loss was obtained by subtracting the final weight from the initial weight of each sample of the polyelectrolyte complex and multiplying by 100. Each sample will be considered a repetition.
  • the pectin showed the characteristic absorption band of the CO group at 1023 cm “ , of the OH group at 3400 cm “ 1 and for the COOH group at approximately 1746 cm “1.
  • the chitosan also presented the absorption band of the OH group at 3411 and the absorption bands in the region of the fingerprint corresponding to the CO group, presented an absorption band at 1654 cm “1 corresponding to the amine group I.
  • a total of 4 formulations were prepared, according to the number of possible combinations having 2 variables for each of the cationic and anionic polymers: the pK and the optimum pH obtained from the potentiometric titrations.
  • formulation D with 10.433g was the one that presented the best performance in the formation of CPE, followed by formulation B with 8.66g and formulations A and C.
  • the Tukey multiple range test was carried out at a significance level of 0.05, for the experiments of the average performance of the CPE in wet weight and dry weight, showing 4 different homogeneity groups for wet weight yields and 3 groups of homogeneity for dry weight yields see (Table 7 and 8).
  • formulations B and D were selected to optimize the cationic polymer which has a higher cost than the anionic polymer that is easily available in the Mexican market.
  • the average wet weight yield of CPE showed a higher yield in the D3 formulation with 64.35g followed by very little difference in the weight of the DI and D2 formulations and finally the D4 formulation see ( Figure 12) .
  • the formulation that presented the best yield was the DI with 10.433g followed by the D2 and the formulations D3 and D4 see ( Figure 13).
  • a variance analysis was carried out where the average yield difference of the wet weight and the dry weight was evaluated, between the formulations of the same group (Bl, B2, B3 and B4) and DI, D2, D3 and D4).
  • the Tukey multiple range test at a significance level of 0.05 was carried out for the experiments of average CPE yield in wet weight and dry weight of the formulations of group B and D.
  • the Tukey multiple range test was carried out at a significance level of 0.05, for the experiments of average CPE performance in wet weight and weight dry between groups of formulations B and D, showing 6 different homogeneity groups for wet weight yields and 5 homogeneity groups for dry weight yields, see (Table 15 and 16).
  • the polyelectrolyte or white solutions were used and evaluated at different concentrations and pH's to measure their solids retention capacity, the sludge solution was not affected when the polyelectrolyte solution was applied, with which it could be verified that Independent polyelectrolytes do not retain solids, in the case of cationic polyelectrolyte a slight flocculation occurred. .
  • the polymers C-492 and C-494 applied in the sludge solution produced a clarification and retention of solids, these polymers are the point of comparison for us, in terms of retention of solids and clarification of water.
  • formulation D2 The formulation that presented the highest CPE formation performance was formulation D2 followed by formulation B3 and D3 see (Table 21).
  • the biodegradation of the CPE was evaluated at the laboratory level using a strain of Serratia marscensens, from which the inoculum number was standardized at 1.66 * 10 7 cells / ml in each flask.
  • the weight loss of the CPE was evaluated at 0, 7, 14,19,34 and 60 days, with a decrease of up to 50% observed at 7 days, subsequently the weight loss was gradual increasing from day 19 to 34 see la ( Figure 19, 20 a and b), after this Date the sample could no longer be recovered, but its presence could be observed in small fragments distributed in the middle.
  • a viable plaque count was carried out during the same sampling dates of the CPE weight loss, observing an increase in the number of cells / ml at the first 7 days of incubation, subsequently a decrease in the number of cells, however the number of these was not less than the number of initial cells, monitoring was carried out until 35 days see ( Figure 21, 22 a and b).
  • CPE Polyelectrolyte Complexes
  • the intrinsic viscosity was determined for both polymers, and for the chitosan said parameter used in the determination of the PM with the help of the Mark-Houink equation, the PM obtained by viscosimetry was compared with that of the supplier which was determined by Magnetic Resonance Nuclear, the result calculated by viscosimetry was the connection and for cost reasons the method was very cheap and easy to carry out.
  • the CPE obtained from the mixture of pectin and chitosan could not be used for the elaboration of membranes as initially contemplated, because it presented the appearance of a compact hydrogel, said name cannot be fully applied to this CPE until its characterization rheological is not carried out.
  • the formulation with the best results was D3 and as a second option, formulation D2 and DI were presented.
  • the formulation D3 was selected, taking into account the Tukey multiple range test where 2 groups of homogeneity were presented for the wet yield as well as for the dry weight yield, said formulation remained as the better performance;
  • formulation B was compared in the same way against group D and the results obtained from the analysis of variance, as well as the Tukey multiple range test presented to formulation Bl and B2 in the group with the highest CPE yield obtained , the decision was evaluated in the same way according to other parameters already mentioned above such as: ease of preparation, appearance and cost or polymer used, according to the above, formulation D3 was taken into account, which was the best of its group, is low cost, easier to prepare and has a good performance in CPE training.
  • chitosan the adsorption, absorption and chelation capacity for heavy metals such as: Pb, Hg, Zn, Ni, Cu, Cd, Ur, Ag, Co, etc;
  • the chelation capacity of this polymer is due to the ability of its amino and hydroxy groups to act as electron donors (Standford, 1989; Onsoyen and Shaugrud, 1990).
  • Another of the multiple applications of chitosan is due to its cationic property within which is its excellent capacity as a flocculant due to the large number of -NH 3 groups that can interact with negatively charged colloids.
  • Pectma on the other hand due to its ammonium property shortens the blood clotting time and is used in cases of hemonagias.
  • pectma is found as a negatively charged polyelectrolyte and can bind to positively charged heavy metal ions.
  • the affinity presented by this polyelectrolytes is lower and lower for the following metals: Lead (Pb)> Barium (Ba)> Cadmium (Cd)> Stroncio (Sr), continues to decrease in its ability to trap alkaline earth ions and ions alkaline
  • the biodegradation of the CPE was observed as the number of cells of the microorganism increased, which only counted as the carbon source with the CPE, which indicated that the microorganism was using that source to grow and during that growth produced some Orange coloration inside the CPE, the growth of the microorganism was diminished after 14 days, without being less than the initial inoculum.
  • 18 a Sludges from Water Treatment Plants and their Illustrative Treatment with the ammonium polyelectrolyte solution.
  • 18b To the mixture of sludge and anionic polyelectrolyte is added the cationic polyelectrolyte solution.
  • 18c The mixture is stirred until the CPE is formed.
  • Solids are separated from water when the CPE is formed.
  • G.I. available ionizable groups per gram of sample.
  • Dr relative viscosity
  • Dr / c viscosity Table 4.- Determination of the Intrinsic Viscosity of Chitosan.
  • Dr relative viscosity
  • Dr / c viscosity
  • GI ionizable groups per gram of chitosan.
  • PSO Weight of the chitosan subunit.
  • Moles of N- moles of N-acetyl Table 6.- Results obtained in the CPE formation of formulations A, B, C, and D.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Cosmetics (AREA)

Abstract

L'invention concerne un procédé d'extraction de métaux lourds et solides en suspension par application d'une solution de polyélectrolytes cationique telle que le quitosan et d'une solution de polyélectrolytes anionique, telle que la pectine. Lorsque ces solutions sont en interaction et agissent ensemble, elles forment un complexe polyélectrolytes (CPE) qui retient les métaux lourds présents dans des effluents contaminés. Ce procédé peut être utilisé pour extraire et clarifier des particules contenues dans des effluents contaminés d'origine industrielle et/ou domestique et est notamment utilisé dans l'industrie pharmaceutique et alimentaire. Ce procédé se caractérise en ce qu'il utilise des produits biodégradables et abondants dans la nature.
PCT/MX2003/000044 2002-05-27 2003-05-22 Procede d'extraction de metaux lourds et solides par formation d'un complexe de polyelectrolytes biodegradables (pectine et quitosan) Ceased WO2003099729A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2003230443A AU2003230443A1 (en) 2002-05-27 2003-05-22 Method of removing heavy metals and solids by complexing biodegradable polyelectrolytes (pectin and chitosan)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
MXNL02000016 MXNL02000016A (es) 2002-05-27 2002-05-27 Procedimiento para remover metales pesados y solidos, mediante el acomplejamiento de polielectrolitos biodegradables (pectina y quitosan).
MXNL/A/2002/000016 2002-05-27

Publications (1)

Publication Number Publication Date
WO2003099729A1 true WO2003099729A1 (fr) 2003-12-04

Family

ID=33536489

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/MX2003/000044 Ceased WO2003099729A1 (fr) 2002-05-27 2003-05-22 Procede d'extraction de metaux lourds et solides par formation d'un complexe de polyelectrolytes biodegradables (pectine et quitosan)

Country Status (3)

Country Link
AU (1) AU2003230443A1 (fr)
MX (1) MXNL02000016A (fr)
WO (1) WO2003099729A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9617176B2 (en) 2013-05-29 2017-04-11 Aguas De Manizales S.A. E.S.P. Compositions for water treatment and methods of using thereof
CN109467612A (zh) * 2018-11-01 2019-03-15 山东汇润膳食堂股份有限公司 一种用酒精研磨分离提取三七的方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4382864A (en) * 1980-08-08 1983-05-10 Kurita Water Industries Ltd. Process for dewatering sludges
WO1994018125A1 (fr) * 1993-02-10 1994-08-18 Vanson L.P. Elimination de metaux polyvalents de courants aqueux de rebut a l'aide de chitosan et d'agents d'halogenation
US5433865A (en) * 1994-03-31 1995-07-18 Laurent; Edward L. Method for treating process waste streams by use of natural flocculants

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4382864A (en) * 1980-08-08 1983-05-10 Kurita Water Industries Ltd. Process for dewatering sludges
WO1994018125A1 (fr) * 1993-02-10 1994-08-18 Vanson L.P. Elimination de metaux polyvalents de courants aqueux de rebut a l'aide de chitosan et d'agents d'halogenation
US5433865A (en) * 1994-03-31 1995-07-18 Laurent; Edward L. Method for treating process waste streams by use of natural flocculants

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9617176B2 (en) 2013-05-29 2017-04-11 Aguas De Manizales S.A. E.S.P. Compositions for water treatment and methods of using thereof
CN109467612A (zh) * 2018-11-01 2019-03-15 山东汇润膳食堂股份有限公司 一种用酒精研磨分离提取三七的方法

Also Published As

Publication number Publication date
AU2003230443A1 (en) 2003-12-12
MXNL02000016A (es) 2003-12-02

Similar Documents

Publication Publication Date Title
Morin-Crini et al. Fundamentals and applications of chitosan
Mittal et al. Recent progress on the design and applications of polysaccharide‐based graft copolymer hydrogels as adsorbents for wastewater purification
Cunha et al. Purification of guar gum for biological applications
Oladoja et al. Polysaccharides as a green and sustainable resources for water and wastewater treatment
Sudha Industrial applications of marine biopolymers
Simpson et al. Bioprocessing of chitin and chitosan
US20220356272A1 (en) Processes for extracting and purifying chitin by using green solvents
Anjum et al. Microwave irradiated copolymerization of xanthan gum with acrylamide for colonic drug delivery.
Prasad et al. Recent development in the medical and industrial applications of gum karaya: a review
Saraswathi et al. Seasonal studies on the alginate and its biochemical composition I: Sargassum polycystum (Fucales), Phaeophyceae
TW201944903A (zh) 愛玉子之低甲氧基果膠及其製造方法
Oladoja et al. Mechanistic insight into the coagulation efficiency of polysaccharide-based coagulants
Carvalho et al. Extraction and Purification of Biopolymers from Marine Origin Sources Envisaging Their Use for Biotechnological Applications
Madduma-Bandarage et al. Chitosan: structure, properties, preparation, characterization, modifications, and importance in environmental cleanup
Román-Guerrero et al. Chemically Modified Alginate-Based Hydrogel-Matrices in Drug Delivery
PT1560855E (pt) Polissacarídeo da echinacea angustifolia
CN108383224A (zh) 一种绿色环保除菌的絮凝剂
WO2003099729A1 (fr) Procede d'extraction de metaux lourds et solides par formation d'un complexe de polyelectrolytes biodegradables (pectine et quitosan)
Grobler et al. Cytotoxicity of low, medium and high molecular weight chitosan’s on balb/c 3t3 mouse fibroblast cells at a 75-85% de-acetylation degree
Tanaka et al. Studies on inhibition of intestinal absorption of radioactive strontium. VII. Relationship of biological activity to chemical composition of alginates obtained from North American seaweeds
KR100216301B1 (ko) 탈아세틸화도가 75-100% 인 키토산의 제조방법
Yusan et al. Antibacterial activity of chitosan nanoparticles 4% from blue swimming crab shell waste (Portunus pelagicus) against Staphylococcus aureus
Vold Periodate oxidised chitosans: structure and solution properties
Vani et al. Recent innovations in natural gums based adsorbents for the removal of toxic metal ion from wastewater
Panchal et al. Chitosan as a natural polymer: an overview

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SC SD SE SG SK SL TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP