Water Science and Technology (Nov 2021)
Binary adsorption of [Pb(II) + Co(II)] from aqueous solution using thiolated saw dust
Abstract
Technology advancement has contributed to an increase in industrial activities, resulting in the introduction of metal ions into water resources at concentrations well above the WHO limits. Heavy metals are highly toxic and carcinogenic; they usually occur as multicomponent mixtures in the aquatic environment. In the present study, batch experiments have been conducted to study the dependence of varying concentration, time, pH and temperature on the uptake of Pb(II) as a pure component under equilibrium conditions using thiolated saw dust. Saw dust has been chemically modified with thioglycolic acid and characterised using proximate and FTIR analyses, the degree of thiolation has also been determined. To determine the effect of the presence of Co(II) ions on the uptake of Pb(II) ions, batch experiments for [Pb(II) + Co(II)] mixture have been carried out for concentration ratios of 1:0, 1:1, 1:2, 1:3, 1:4 of Pb:Co at pH 5 and data has been interpreted using Langmuir competitive isotherm, which shows that adsorption of Pb(II) has been suppressed by the presence of Co(II) ions in the binary solution, hence the adsorption process is antagonistic in nature. The study also indicates the possibility of simultaneous removal of both metal ions using low cost bioadsorbent, which is economical especially for application in small-scale industries. HIGHLIGHTS Thiolated saw dust shows excellent ability to adsorb Pb(II) and Co(II) ions.; Binary adsorption is based on electrostatic interaction controlled by the solution pH.; Thermodynamic adsorption behavior depends on adsorbent surface functional groups.; Affinity of each metal ion is depressed by the presence of the other in the binary solution.; Antagonistic effect on adsorption has been observed.;
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