Study on the Structures and Properties of Copper Removal Adsorbent Prepared from Sinter-free Pulverized Oyster Shell Materials

A hollow tubular copper removal adsorbent was prepared with oyster shell and cement as the main raw materials. The effects of different formulas, different initial copper concentrations and different pH values of samples on the copper removal efficiency were investigated to determine the optimal conditions for copper removal. The content of copper in the wastewater is determined by Atomic Absorption Spectrophotometer. The microstructure and elemental composition of the samples were characterized by scanning electron microscopy(SEM) and EDS. As a result, the formula with the content of cement to be 8 wt% and the oyster shell powder of 92 wt% is optimal. Under the condition of 30 ℃, when the pH value was 9.0, the Cu2+ adsorption capacity of the sample could reach 0.59 mg/g at 48 h. SEM analysis revealed that there are abundant pores in the sample, which is beneficial for Cu2+ absorption on the adsorbent.     

Kinetics and Thermodynamics of the Adsorption of Copper(Ⅱ) onto a New Fe-Si Adsorbent

A new kind of Fe-Si adsorbent was synthesized by iron oxide and diatomite after calcining and hydrothermal process. The influences of the initial Cu2+ concentration, p H and adsorption time on the Cu2+ removal efficiency were discussed. Three adsorption empirical kinetics equations and two thermodynamics equations were used to simulate the adsorption process. The microstructures of newly developed copper removal materials and properties of copper removal are characterized in details by SEM and EDS. Adsorption mechanism of the adsorbent was discussed. The suitable p H value for Cu2+ removal is 5.0 to 6.0 and the adsorption capacity increases with increasing the initial Cu2+ concentration. The adsorption kinetics of the adsorbent could be better described by pseudo second order kinetic model, whereas the adsorption isotherms highly conform to the Freundlich equation. The main crystalline phase of the adsorbent is Fe(Si O3) which can build porous structures conducive to the Cu2+ adsorption.