Acta Montanistica Slovaca (Nov 2005)
Arsenic and nickel removal from water resources by adsorption
Abstract
The adsorption of arsenite and arsenate onto Mg(OH)2 is governed by the form of arsenic species in water. The Langmuir and Freundlich isotherm equations and Original 6.0 professional (non-linear curve fit) were able to describe the arsenate adsorption process. The Langmuir isotherms constants, which relates the adsorption energy, indicated a strong binding force between arsenate and the surface of Mg(OH)2. All calculated values of the separation factor RL showed that Mg(OH)2 is a favourable adsorbent to uptake AsV from aquatic solutions at different initial concentrations. The separation factor’s value for arsenite was almost one (RL=1 means that the shape of the isotherm is linear). It means that Mg(OH)2 is unfavourable for AsIII. The Removal of arsenate by common water treatment processes (coagulation, precipitation, or adsorption on to hydrated oxides of Fe3+ or Al3+) makes no problem. The Removal efficiency of AsV for the initial concentration 10 mg/l is up to 95-98 %. In case of AsIII, the maximum efficiency is only about 50 %.
