Abstract
In the present study, the microalga Rhizoclonium hookeri (RH) was effectively applied to remove the metal ions [Pb(II) and Ni(II)] from aqueous solution in batch adsorption mode experiments. The adsorption process was influenced by several operating parameters such as initial metal ion concentration, contact time, pH, particle size, adsorbent dose, and temperature. The maximum monolayer adsorption capacity of the RH was found to be 81.7 mg g−1 and 65.81 mg g−1 for Pb(II) and Ni(II) ions, respectively, at optimum conditions. The calculated thermodynamic parameters illustrated that the adsorption process was found to be spontaneous and endothermic in nature. Experimental data were analyzed in terms of pseudo-first order, pseudo-second order, and Elovich kinetic models. The results showed that the removal of Pb(II) and Ni(II) ions followed the pseudo-second order kinetics. The adsorption isotherm data were described using two and three parameter models. The results indicate that the adsorption data were best fitted with the Sips isotherm model. Consequently, the microalga RH with good adsorbability and reusability could be used as an effective adsorbent for the adsorption of Pb(II) and Ni(II) ions from wastewater.
Highlights
Industrial and domestic wastewater has become a serious threat to water resources around the world
The effect of temperature on the adsorption of Pb(II) and Ni(II) ions using the microalga Rhizoclonium hookeri (RH) was examined at different temperatures (25 to 40 WC) with a fixed initial metal concentration (1,000 mg LÀ1) at the adsorbent dose of 1 g LÀ1 and at a pH of 4.5
The results suggest that the adsorption process of Pb(II) and Ni(II) ions is endothermic in nature which means that the adsorption capacity was directly proportional to the solution temperature
Summary
Industrial and domestic wastewater has become a serious threat to water resources around the world. Pb(II) and Ni(II) ions in drinking water has been fixed at 0.01 and 0.02 mg/L (Bureau of Indian Standards ) These metal ions are mostly released in excess amount from industries such as electroplating, metal finishing, porcelain enameling, paint and dyes, vegetable fat producing industries, lead batteries, electroplating, mining and smelters as well as other industrial, urban, and agricultural activities (Anbalagan et al ). Bioaccumulation of these metals may cause longterm health hazards such as skin allergies, lung fluorosis, cyanosis, nausea and vomiting, different degrees of poisoning to the kidney, and affects the cardiovascular system, liver, central nervous system, and gastrointestinal system (Fu et al ).
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