Comparative Study On Effect Of Various Biological Materials Adsorbing Heavy Metals

Using biological materials to treat wastewater is a new type of technology which developing in recent years. It is particularly suitable for dealing with low concentrations of heavy metals in wastewater. In addition, the method has an advantage of wide source of raw materials, good adsorption effect, and it shows a greater advantage in the cost of raw materials and environmental protection, so it has broad application prospects.Agricultural waste orange peel, natural polymer chitosan materials and industrial waste fly ash cenosphere were chosen as the adsorption material. After modified, they were used as adsorbent treating Pb2+ and Cr6+ solution. Then adsorption properties of biological materials were studied.First of all, orange peel and chitosan was immersed by ethanol and NaOH solution. Iron oxides, rare earth oxides Sm and cenosphere were prepared to made magnetic nanocomposites, then the same way to treat it. The treatment is used to improve their adsorption properties. Secondly, the effects of various parameters, including solution pH, adsorption time and metal ions concentration, amount of the adsorbent materials and temperature on the adsorption process were investigated by using batch adsorption techniques, then find their optimum adsorption conditions. The results showed that the greatest impact absorption effect is to change the pH value; each material has its own optimum adsorption amount adsorbed. The adsorption kinetics performance comparison of the three materials had been analyzed. Some scientific basis for containing low concentrations of Pb2+ and Cr6+ wastewater treatment can be provided.The results showed that ion concentration of Pb2+ and Cr6+ can effectively be reduced by three biosorption materials. The adsorption rate for modified orange peel of Pb2+ can reach 94.5% and reach 83.89% of Cr6+. The adsorption rate for modified chitosan of Pb2+ can reach 98.3% and reach 87.81% of Cr6+. The adsorption rate for modified cenospheres of Pb2+ can reach 99.7% and reach 91.49% of Cr6+. Scanning electron microscopy and infrared spectroscopy had been used to determine their adsorption mechanism.