ABSTRACT
Drinking water treatment residuals [DWTRs] at rates of 2, 4, 6, and 8% were evaluated for their effectiveness in the immobilization .of Cu, Cd, and Pb in Abu-Rwash contaminated soil. Sequential extraction technique was used to investigate the changes in the metal forms and fractions before and after addition of DWTRs. These metals form were also examined after 12 and 60 days of incubation periods. In addition, the bioavailability of metals expressed by DTPA-extractant was utilized to follow the bioavailable form of metals as a result of adding DWTRs within the two incubation periods [12 and 60 days]. The results showed that after the Abu-Rwash soil was treated with the DWTRs at rates of 2, 4, 6 and 8 %, the three metals were transformed into more stable forms, and this effect increased as the increase of rate of DWTRs and incubation time; since more residual fraction for Cu and more oxide and residual fractions for Cd and Pb in the soils were found. In addition, DTPA-extractable metals significantly decreased as both DWTRs rate and incubation periods increased. The final results verify the aptitude of DWTRs application to ameliorate the risks of heavy metals in Abu-Rwash contaminated soil
ABSTRACT
This work describes preparation of new chelating materials derived from cellulose for adsorption of Cu+"ion from aqueous solutions. The first part involved treatment of cellulose with NaOH, NH4OH, citric acid, oxalic acid and ferric chloride and chelation processes. The products of the above treatments were subjected to elemental analysis, infrared spectra and X- ray powder diffraction. The second part consists of evaluating the adsorption capacity of the none- modified and modified materials for Cu[+] ions from aqueous solutions. Plence, influences of contact time. pH, and initial concentration of Cu[+], on the adsorption process were determined. Maximum adsorption capacities of the modified materials for Cu+2 ions ranged from 46.73 to 188.68, whereas for non-modified cellulose presented 14.33 mg g. The optimum pH value was found to be 6 and the reaction balance was reached after 75 min. Pseudo first and second order kinetic models were fitted to the obtained data indicating different mechanisms for Cu[+] bio-sorption. Among different models used to describe sorption and kinetics of the experimental data, the Langmuir and Freundlich isotherm models are found to better fit the results. We conclude that the chemically modified cellulose materials can be efficiently used to remove Cu[+] from aqueous solutions
ABSTRACT
This work describes preparation of new chelating materials derived from cellulose for adsorption of Cu[+] ion from aqueous solutions. The first part involved treatment of cellulose with NaOH, NH4OH, citric acid, oxalic acid and ferric chloride and chelation processes. The products of the above treatments were subjected to elemental analysis, infrared spectra and X- ray powder diffraction. The second part consists of evaluating the adsorption capacity of the none- modified and modified materials for Cu[+] ions from aqueous solutions. Hence, influences of contact time, pH, and initial concentration of Cu[+] , on the adsorption process were determined. Maximum adsorption capacities of the modified materials for Cu[+] ions ranged from 46.73 to 188.68, whereas for non-modified cellulose presented 14.33 mg g. The optimum pH value was found to be 6 and the reaction balance was reached after 75 min. Pseudo first and second order kinetic models were fitted to the obtained data indicating different mechanisms for Cu[+] bio-sorption. Among different models used to describe sorption and kinetics of the experimental data, the Langmuir and Freundlich isotherm models are found to better fit the results. We conclude that the chemically modified cellulose materials can be efficiently used to remove Cu[+] from aqueous solutions