Preparation Of Novel Absorption Materials And Adsorption Properties Of Cu(â…¡) From Wastewater

Heavy metal ions contamination has been given great concern in recent years due to their hardly biodegradation, accumulation, toxicity and carcinogenicity in living organisms. Copper is an essential element for all living organisms, which are incorporated into a number of metalloenzymes. The deficiency of copper results in severing health problems. On the other hand, excess of copper is toxic. Bentonite and silica gel which has certain adsorption performance, are widely applied in the removal of metal ions from waste water. In this study, the MnO2-modified bentonite adsorbents removal of Cu2+from etching wastewater and poly(ethyleneimine)-functionalized silica adsorption removal of Cu2+ from electroplating wastewater have been developed and were characterized by FTIR, BET, SEM and XRD. Their adsorption behavior were then investigated toward Cu2+. Following major elements:In this study, the MnO2-modified bentonite adsorbent has been developed successfully as an effective adsorbent for the adsorption removal of Cu2+ from etching wastewater. The effect of process parameters such as pH, agitation time and initial concentration were investigated by using batch experiments. The results indicated that the maximum static adsorption capacity of Cu2+on manganese dioxide-coated bentonite was found to be 32.4 mg/g, much higher than natural bentonite(16.2 mg/g).The pH dependent sorption of Cu2+ was found maximum at 5.0. The equilibrium contact time was 60 min for both of the adsorbent. The adsorption kinetics data of Cu2+on MnO2-modified bentonite adsorbent was well described by a pseudo-secondorder model. The Langmuir adsorption model was more favorable than the Freundlich adsorption model. Various thermodynamic parameters such as ΔGo, ΔHo and ΔSo revealed the spontaneity and exothermic nature of the adsorption process. The optimum dosage of MnO2-modified bentonite adsorbent for the removal Cu2+from etching wastewater was 8.5 g/L. The removal efficiency of Cu2+ from etching wastewater was 91.9%. The results showed that the MnO2-modified bentonite adsorbent was an effective adsorbent for the removal of Cu from etching wastewater.The poly(ethyleneimine)-functionalized silica has been developed successfully as an effective adsorbent for the adsorption removal of Cu2+ from electroplating wastewater. The influences of pH, contact time and initial concentration of Cu2+ on the adsorption capacity and the effect of adsorbent dosage on the removal efficiency of Cu2+from electroplating wastewater were investigated. The adsorption behaviors and mechanisms of Cu2+ onto poly(ethyleneimine)- functionalized silica were also studied in details. The optimum pH values were found to be as 4.00 and 8.00. The poly(ethyleneimine)-functionalized silica offered a fast rate and the equilibrium contact time was 30 min. The results of static batch experiment indicated that the maximum static adsorption capacity of Cu2+ on PEI-functionalized silica was 31.8mg/g. The adsorption process was found to follow a pseudo-second-order ratemechanism. Langmuir adsorption isotherms fitted well in the experimental data. The optimum dosage of poly(ethyleneimine)-functionalized silica for the removal Cu2+from electroplating wastewater was 10 g/L. The removal percentage of Cu2+ from electroplating wastewater was 92.6%. Results of this work show that poly(ethyleneimine)-functionalized silica is a promising adsorbent for Cu2+ from wastewater.