Study On Removal Efficiency Of Composite Chitosan In Waste Water Treatment

Nowadays, Chitosan as a non-toxic natural amino polymer functional material, have been applied gradually gained popularity in waste water treatment. This paper has researched the remove efficiency of pollutant using some new composite chitosan adsorbents and introduces the research and application of Chitosan on environmental pollution regulation in drinking water treatment and sludge dewatering.Chitosan(CTS) is obtained by deacetylation of Chitin which is extracted from crustacean or from fungal biomass. Chitosan is a biodegradable, non-toxic, linear cationic polymer of high molecular weight and is a potent coagulant .Because a amount of dissociate amino groups exist chitosan macromolecule chain and it can be proton change in acidic solution. The high proportion of amine functions in this natural polymer results in novel binding properties for some kinds of dyestuffs, metal ions and protein. Chitosan was regarded as an amino polysaccharide and a soluble cationic coagulant. These cationic groups and negative ion colloid particulate attract each other and neutralize colloid surface charge. Because of the more coiled structure, chitosan polymer is able to compress pervation layer to take steady.In virtue of charge neutralization and adsorption and bridge connection effect so as to produce larger and denser flocs and affluent–NH₂ and–OH was used as absorbent for heavy metals.Technologies for dye removal have been investigated, such as the electrolysis coagulation, chemical oxygenation, those processed condition is strict, the stability is bad. The article intends to introduce the authors'experimental study on four kinds of adsorbents which are made by chitosan-coated bentonite , chitosan-coated pearl, carboxymethyl chitosan-coated bentonite and carboxymethyl chitosan-coated pearl .The ability of chitosan-coated bentonite for the removal of reactive dye ,namely reactive red B-3G, blue B-2GLN, black B-GRFN, green B-4BLN,from aqueous solution has been studied. The experimental equilibrium data have been analyzed using the linearized forms of Langmuir, Freundlich isotherms .The Langmuir isotherm was found to provide the best theoretical correlation of the experimental data for the adsorption of all four reactive dyes. The monolayer adsorption capacities were determined to be11.850,7.760,7.276,8.362mg of dye per gram of chitosan-coated bentoniteadsorbent,respectively to four dyes. The results would provide a theoretical basisfor utilizing natural material to extract heavy metals from the contaminated soils.The adsorption of dyes onto Carboxymethyl chitosan adsorbent was expensiveprocess with high capacities. The paper also studied the application of adsorptionof Acid Brilliant Scarlet GR onto Chitosan-coated cellulose adsorbent has beenstudied. It was a fast process and K₁=0.884 h^-1. in Lagergren equation.The adsorption of BSA onto sphere Chitosan polymer has been experimented.Effect of amount of agents, pH value, adsorption time and ionic strength werestudied. The research results for coagulation of dairy producted wastewatersshow that the recovery efficiency of protein by chitosan was efficient. Theexperience of adsorption of Cd²⁺ and Al(â…¢)showed that the adsorption was a fastprocess with 254.5mg·g^-1,49.0mg·g^-1.capacity. Chitosan-Cd(â…¡), Chitosan- Al(â…¢)PPwas synthesized and FTIR, XPS analysis indicates that the adsorption was thecoordination of -NHB2 Band -OH groups of Chitosan to Cd²⁺.The study assessed the feasibility of the application of chitosan for thecoagulation of kaolinite colloidal particles. The pH effect on the coagulationefficiency of chitosan is insignificant. The evidence infers that chargeneutralization is not a major mechanism controlling the formtion of floc forchitosan coagulation and the water conservancy condition is the key factorcongealed. Chitosan was used to enhance the flocculation treatment of thesurface water,which is the raw water of Yellow River in Zheng Zhou bypolymeric aluminum chloride (PAC).The improvement of removal efficiency ofturbidity and COD indicated that chitosan could enhance the flocculationtreatmen by PAC significantly. When PAC dosage is 35 mg·l^-1, CTS dosage is0.15 mg·l^-1, the effect of flocculation is better. Zeta potential instrument andScanning electron microscope were used to test Zeta potential and observe thestructure of flocs and infer flocculation mechanism was interpartical bridgingrather than the electrical neutralization by prositive charge. The floc wasobserved with microscope and image analysis system and the result show thatvariation in fractal dimension can make good response to flocculation level andPAC,PAC/CTS was 1.294,1.385 respectively. The effect of the dosage of flocculants on activated sludge dewatering is analyzed through the determination of sludge specific resistance to filtration . Sludge dewatering behaviors conditioned on PAC, CTS and composite flocculants have been compared. The results show all the conditioning agent have help to sludge dewatering .Compared with Polymeric aluminum , Chitosan and PAC/CTS composite coagulant, the optimum coagulant with its optimum dosage is obtained . PAC/CTS can greatly reduce the sludge specific resistance and improves the sludge dewatering performance largely while the clarity of the filtrate was high. While designing the dewatering and drying process of sludge water from water works, we can ignore the coagulation process, and utilize fly ash of power plant as the conditioner of sludge from water works directly.