Adsorption potentiality of biomaterials and biogeocomposites in removing copper from aqueous solution

Abstract

In the present experimental work, through batch experiments and column studies, biomaterials like papaya leaf powder and paddy straw powder were used as adsorbents for the removal of copper from wastewater. The biomaterials were cleaned, washed, dried and powdered before use without any chemical treatment. Both the materials indicated good percentage removal of copper from industrial wastewater, which is a major source of concern in the study area. In the batch experimental studies, a maximum of 90-95 % removal of copper was obtained under optimum conditions with reference to the controlling parameters, such as, time of contact, dosage of adsorbent, pH and initial concentration. The equilibrium time, which is defined as the minimum time taken for maximum removal of the metal, was found to be 60 minutes for papaya leaf powder and 90 minutes for paddy straw powder. The optimum pH at which maximum adsorption took place was found to be 7. newlineThe experimental data from batch studies were compared and verified by the existing well known pseudo second- order kinetics equation, and intraparticle diffusion model. It was recognised that pseudo-first-order model did not fit the experimental data well. FTIR studies conducted for both the adsorbents, before and after the adsorption process, have shown that the bands shifted slightly, after the adsorption of copper, indicating the participation of the functional groups in the adsorption process. A multi metal adsorption study was also conducted to find the effect on removal of copper due to the presence of other metals and it was found that the removal was slightly affected. newlineFixed column experiments were also conducted to understand the efficiency of the removal of heavy metals. The breakthrough curve for both the adsorbents were S shaped which depict the increase in the effluent concentration as sorption zone moves through the column. To enhance the adsorption of copper, geotextile material was also experimented with biomaterials in dynamic mode studies. It was found that the removal of copper increased by 10-15 % with the incorporation of geotextile material. Further, it was also found that the breakthrough time and percentage removal was decreased when the initial metal (influent) concentration increased. The performance of bio-geocomposites developed with geotextile and adsorbents were found to be better than the adsorbents when used alone. newline newline