Cadmium and copper adsorption on bentonite: effects of pH and particle size

Abstract

Reactions of heavy metals with clay minerals are important in determining metal fates in the environment. However, the adsorption process of these metals by the bentonite has been extensively investigated. The objectives of this work were to assess the ability of bentonite clay to adsorb cadmium and copper and to study the effects of pH and particle size upon these metals adsorption. Adsorption isotherms were obtained from batch adsorption experiments, with increasing cadmium and copper concentrations (5-200 mg L-1). To find out the effects of pH and particle size on adsorption, the experiments were conducted at pH 4; 5 and 6 using particles sizes of < 0.5 mm and 0.5 to 2.0 mm. The difference between initial and final cadmium and copper concentrations was assumed to be the amount adsorbed by bentonite. The bentonite adsorbed more copper than cadmium, both metals adsorption increased with increasing pH for both particle sizes. No effect of particle size was observed. Experimental data were best fitted to Langmuir model.

Assessment of the Levels of Potentially Toxic Elements Contained in Natural Bentonites Collected from Quarries in Turkey

“…From this point of view, it is important to know the concentrations of PTEs contained in bentonites. Until now, many studies on the absorption/adsorption and desorption of PTEs or heavy metals by bentonites have been published in the literature. − However, according to our literature research, there is no detailed study on the determination of PTE concentrations in bentonites. This study aims to determine the concentrations of PTEs (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Zr, and Pb) in 72 bentonite samples collected from quarries located in different geographical regions of Turkey using energy-dispersive X-ray fluorescence (XRF) spectrometry and calculate the enrichment factor to Earth’s crustal average of the PTEs.…”

Adsorption of Heavy Metals on Bentonitic Soil for Use in Landfill Liners

“…In addition, feldspars and ferromagnesian minerals rapidly decompose in semiarid regions, whereas the concentration of iron and aluminum oxides remains stable [32]. The sorption of heavy metals in soils from the Brazilian semiarid region was analyzed by researchers such as Chaves and Tit [33], Vasconcelos et al [34], Meneguin et al [35], Araujo et al [36], and Barros et al [37].…”

Clays, Limestone and Biochar Affect the Bioavailability and Geochemical Fractions of Cadmium and Zinc from Zn-Smelter Polluted Soils

“…The in-situ fixation of TE(s) by organic or synthetic additives, e.g., clay additives [10, [11], phosphate compounds [12], bio-solids [13], and alkaline material [14], is a promising option for cleanup of inorganic pollutants in contaminated sites because this method if cheap, feasible and environmentally friendly [15]. Subsequently, Chaves and Tito [16] stated that reactions of TE(s) with clay additives are very imperative for influential metal compounds in the surroundings. Moreover, Yi [17] reviewed that clay additives have great potential to enhance soil pH, which may account for reduced chemical-extractable fractions and the bioavailability of metal-polluted soil and restrict their accumulation in plants.…”