Use Crayfish Shell Prepared Chitin-bentonite Composite Biological Adsorption Materials And Chromium Removal Research

In this paper, one of heavy metal pollutants chromium as the main object of study,choose water systems for human survival as the research environment.The use of crayfishshell prepared chitosan，and then preparation crosslinked chitosan-coated bentonite beads.And then use chitosan, bentonite and crosslinked chitosan-coated bentonite beadstreatment of wastewater containing chromium respectively, compared Cr (Ⅵ) removal.The first is the use of crayfish shell preparation of chitosan, the experiment using thetraditional method dragons shrimp processing, the use of acid soaking, oxidation and othermethods to remove dragons shrimp in calcium, protein and pigment prepared chitin. Thetraditional method is simple, easy to carry, and are subject to less restrictive conditions.Experiments show that crayfish shell containing chitosan and chitosan prepared the finally,but due to differences in the preparation process, chitosan derived only10%to20%atlast.The results of chitosan treatment of wastewater containing chromium showed that: thebest dosage of chitosan was8g/L, the removal efficiency of around74%; optimum pHvalue was2-3; optimum treatment temperature was30℃; optimum mixing time was50mins.The results of bentonite treatment of wastewater containing chromium showed that: asthe increase of dosage, the removal efficiency increases. when the dosage of more than0.5g, Cr (VI) removal almost no change, then Cr (VI) removal rate of about27percent,Unmodified bentonite for Cr (VI) removal little.The use of the prepared chitosan and natural bentonite preparation of crosslinkedchitosan-coated bentonite beads which is the composite biological adsorption material.Form the characterization of chitosan-coated bentonite composite adsorbent material, weknow that the composite material containing-OH,-NH, C-O-C etc. groups. Its BET specificsurface area is15.3113m2/g. Average adsorption pore width (4V/A by BET):6.52659nm. Crosslinked chitosan-coated bentonite beads treatment of wastewater containingchromium showed that: the best dosage of crosslinked chitosan-coated bentonite beads was1g/L, chromium removal efficiency reached86.84%; optimum pH value was about6;optimum processing temperature is50℃; optimum mixing time of40mins.Preparation of chitosan-coated bentonite composite adsorbent material for biologicalremoval of hexavalent chromium is more obvious than the chitosan and bentonite have adistinct advantage.