Adsorption Behaviors Of Cr(Ⅵ) On Different Adsorbents

The economic growth mode of China’s industry is the extensive economic growth mode. Associated with the disorder of "waste residue, waste water, waste gas" emissions, resulting in haze, the water pollution, groundwater can’t drink such as environmental pollution incidents, seriously affect the production and living order. High concentration of heavy metal ion in industrial wastewater discharged directly, it will cause or do not discharge standards, surface water, groundwater, soil and other serious pollution, endanger human health. Therefore, test study on cheap adsorbents to remove heavy metal ions in industrial wastewater, not only has important theoretical value, and has significant economic and social benefits.This paper adopts batch experiment on the fly ash, pine nut shell, acid modified bentonite on the adsorption properties of Cr (Ⅵ), and mainly analyzes the solid-liquid ratio, pH, temperature and adsorption kinetics, the concentration of Cl" on the influence of the adsorption properties of Cr (Ⅵ). Basically have the following conclusion.(1) Three kinds of adsorbent on adsorption of Cr (Ⅵ) with the following rules. When the adsorbent dose increases, the higher the removal rate of Cr (Ⅵ), and the adsorption quantity reduced. Acid condition is conducive to Cr (Ⅵ) adsorption, when pH=1-3, adsorption capacity is the largest. In Cl-solution, Cr (Ⅵ) adsorption capacity decreased with the increase of the concentration of Cl-, indicates that there is competition between the two. The desorption experiment results show that the three kinds of adsorbent for Cr (Ⅵ) adsorption stability are good.(2) Fly ash adsorption of Cr (Ⅵ) is the exothermic reaction. Pine nut shell and H+-bentonite adsorption of Cr (Ⅵ) are the endothermic reaction. In the acidic environment, Langmuir model and Freundlich model can be used to describe the fly ash adsorption of Cr (Ⅵ), using the Langmuir model describing pine nut shell with acid modified bentonite adsorption of Cr (Ⅵ).(3) Three kinds of adsorbent adsorption of Cr (Ⅵ) is the process of rapid response, H+-bentonite adsorption rate was the fastest. The kinetic data fit the pseudo-second order kinetics very well.