Heavy Metal Ion Wastewater Traetment By Newly Bioabsorbent

Biosorption is a new way to treat wastewater containing heavy metal ions. As we all know, ordinary adsorbents have two disadvantages:low adsorption capacity and secondly pollution, which limit the application of the biosorption. Soyebean hulls adsorbent is a kind of promising bioadsorbent, which overcomes the disadvantages mentioned above.The preparation process of soybean-hulls adsorbent was optimized by changing pretreatment methods and solidify reagent quantity. The best reaction way and reaction condition was chosen, which was using O.IM NaOH as pretreatment agent and0.6M citric acid(CA) as reagent.The static adsorption and static adsorption performance were studied. The maximal absorption capacity of modified soybean hulls for Pb2+was above210mg/g, and the temperature and metal ions (Ca2+, Mg2+, Na+) in solution hardly influence the adsorption. The best pH environment was6to8.The optimal desorption-regeneration condition was using0.05mol L-1HCl as desorbent and0.05mol L-1NaOH as regeneration reagent. After using5batches, the adsorption capacity for Pb2+could reach80%of that of the first batch. Since the original limitations on density and strength of soybean, balling of the soybean hulls is studied. It is shown that the optimal balling condition was that CTS:soybean hulls is1to4. The modified soybean hulls can be used twice.Effect of ultrafilter, microfiltration and enzyme on leather wastewater COD removal was investigated. Using ultrafilter, microfiltration and enzyme as pretreatment of bioadsorption process with expand-bed was studied. The removal ability and effects of organics pollutant on leather wastewater was not as well as we hope. Besides, a new facility of Chrome Tanning effluent treatment had been built in Xin ji of He Bei province. Combining expanded bed, aeration treatment and chemical sedimentation,500t/a wastewater could be treated by the new facilities. Through expanded bed treatment, the total Cr concentration of leather wastewater decreased to less than l.Omg/L, the COD decreased to150mg/L and the SS decreased to15mg/L. the treated wastewater can be reused to soak and wash skins.