مرکز منطقه ای اطلاع رساني علوم و فناوري - Synthesis of various layered double hydroxides using aluminum dross generated in aluminum recycling process

Latin Abstract :

The synthesis of Mg–Al, Ca–Al and Zn–Al type layered double hydroxides (abbreviated as LDHs) was carried out using aluminum dross leachates dissolved with HCl and NaOH solutions. Of concern in this study is the preparation of LDHs from secondary wastes and the relative performance of the resulting LDHs as an anion exchanger for the inorganic ions including Cr(VI), B, As(III) and Se(IV) and organic compounds including terephthalate and dodecyl sulfate ions. uminum dross was effectively leached with HCl and NaOH. However the use of HCl, which although effectively dissolved the dross (65%), showed little selectivity for Al leaching. Whereas NaOH showed lower metal dissolution (36%) but resulted in purer solution (96% Al). Various LDHs including Mg–Al, Ca–Al and Zn–Al type were prepared by co-precipitation of metals from the aluminum dross leachates. No noticeable differences in the XRD pattern, thermogram and anion exchange capacity among the various LDHs were found. The presence of other metal impurities did not significantly affect the performance of LDHs prepared. The Mg–Al LDH captured about 85% to almost 100% of anionic organic and inorganic species from the dilute solution, showing the best performance among the LDHs tested. This study has demonstrated the preparation and efficacy of Mg–Al, Ca–Al and Zn–Al type LDHs prepared from aluminum dross and thus the potential of this technology for reusing this secondary waste.