Widi Astuti, Achmad Chafidz, Ahmed S. Al-Fatesh, Anis H. Fakeeha
Coal fly ash (CFA) is composed of minerals containing some oxides in crystalline phase (i.e., quartz and mullite), as well as unburned carbon as mesoporous material, thus enabling CFA to act as a dual-sites adsorbent with unique properties. This work focused on the adsorption of Pb(II) and Zn(II) from binary system, a mixture containing two metal ion solutions present simultaneously, onto NaOH-modified CFA (MCFA). Several adsorption tests were conducted to evaluate the effect of several parameters, including pH and contact times. The experiment results indicated that chemical treatment of CFA with NaOH increased pore volume from 0.021 to 0.223 cm3·g−1. In addition, it could also enhance the availability of functional groups on both minerals and unburned carbon, resulting in almost 100% Pb(II) and 97% Zn(II) adsorbed. The optimum pH for adsorption system was pH = 3 and quasi-equilibrium occurred in 240 minutes. Equilibrium data from the experimental results were analyzed using Modified Extended Langmuir (MEL) and Competitive Adsorption Langmuir-Langmuir (CALL) isotherm models. The analysis results showed that the CALL isotherm model could better describe the Pb(II) and Zn(II) adsorption process onto MCFA in binary system compared with MEL isotherm model. © 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd
Chemical Engineering Department, Universitas Negeri Semarang, Semarang, 50229, Indonesia; Chemical Engineering Department, Universitas Islam Indonesia, Yogyakarta, 55584, Indonesia; Center for Material Science and Technology Studies, Chemical Engineering Department, Universitas Islam Indonesia, Yogyakarta, 55584, Indonesia; Chemical Engineering Department, King Saud University, Riyadh, 11421, Saudi Arabia
