Study On Preparation And Adsorption Properties Of Polyhydroxyl Iron-Chitosan Modified Bentonite

Polyhydroxyl iron-chitosan modified bentonite was prepared under mircrowave irradiation using a bentonite from Guangxi Ningming as raw material, Polyhydroxyl iron and chitosan as modifier in this paper. Polyhydroxy Iron-chitosan modified bentonite structure was characterized by the test techniques as X-ray diffraction (XRD) analysis and fourier transform infrared spectra (FTIR). With Simulated wastewater (reactive red X-3B wastewater, Cr (VI) wastewater, the co-existenced system of2,4-dichlorphenol and Cd2+) and practical wastewater as treatment object, the adsorption capacities of Polyhydroxy iron-chitosan modified bentonite was investigated. The main research contents as follow:Firstly, the optimum preparation conditions under microwave irradiation Polyhydroxy iron-chitosan modified bentonite were determined.Secondly, Polyhydroxy iron-chitosan modified bentonite structure was characterized. XRD analysis showed that after modified by polyhydroxy iron and chitosan, the interlayer distance of bentonite was expanded, Which indicated that the Polyhydroxyl iron and chitosan had entered into the interlayer of bentonite. The FTIR analysis result showed that Polyhydroxy iron-chitosan had static electrostatic interaction with bentonite.Thirdly, the adsorption capacities of Polyhydroxy iron-chitosan modified bentonite to reactive red X-3B, Cr (VI), the co-existence of2,4-dichlorphenol and Cd2+was investigated. The effects of the dosage of adsorbent, solution pH value and adsorption time on the adsorption capacities of Polyhydroxy iron-chitosan modified bentonite was studied.The result showed that Polyhydroxy iron-chitosan modified bentonite had high adsorption capacities for reactive red X-3B, and the decolorization rate could achieve93.5%, whose isotherm was in accordance with Langmuir isotherm equation. The maximum removal rate of it on Cr (VI) could reach94.25%and the adsorption isotherm was well represented by both the Langmuir and Freundlich isotherm models. The cooperated adsorption capacities of Polyhydroxy iron-chitosan modified bentonite to2,4-dichlorphenol and Cd2+were also high, the removal rate reached90.25%and96.40%respectively, the adsorption processes followed the Langmuir adsorption isotherm equation.Fourthly, the adsorption capacities of Polyhydroxy iron-chitosan modified bentonite to the practical wastewater—filature wastewater was investigated. The result showed that under the optimum conditions the removal rate of COD could achieve90.56%.Compared with raw bentonite and Na-bentonite, the processing capacity of Polyhydroxy iron-chitosan modified bentonite was greatly enhanced in filature wastewater.