Simultaneous adsorption of Cd, Cr, Cu, Pb, and Zn by an iron-coated Australian zeolite in batch and fixed-bed column studies

Abstract

Excessive levels of heavy metals in water are an environmental hazard. An Australian zeolite with (ICZ) and without (Z) iron-coating, was used to remove five heavy metals from aqueous solutions using adsorption in batch and column experiments. The batch study showed that the Langmuir adsorption capacities of heavy metals on Z and ICZ at pH 6.5 and ionic strength 10-3 M NaNO 3 were in the order Pb > Cu > Cd > Cr, Zn for single metal (5.0-11.2 mg/g) and for mixed metals solution (3.7-7.6 mg/g). The data for the kinetics of adsorption satisfactory fitted to both the pseudo-first and second order models with fits slightly better for the latter model. Data fitted to a diffusion model revealed that adsorption took place in two or more than two different stages: a fast external surface adsorption, and a gradual adsorption controlled by both film diffusion and intra-particle diffusion. The column adsorption data were fairly well described by Thomas model, with the order of Thomas adsorption capacity following a similar trend as in the batch study. In both batch and column experiments, the adsorption capacities were higher for ICZ than for Z and were generally lower in mixed metals system than in single metals system. Leaching of used ICZ columns with 0.1 M HCl, resulted in 64-93% of adsorbed metals being desorbed, and 10% of Fe being dissolved from the ICZ.

Transport of Nitrogen Compounds through Subsoils in Agricultural Areas: Column Tests

“…Based on the definition of the retardation factor [38], the velocity of NH 4 + transport was less than the velocity of the water flow (6.99 and 5.08 times for UDS2 and the sand sample, respectively). The dynamic ), and the dynamic sorption capacity for the exhaustion point was smaller than the sorption capacity calculated from the batch test and commonly reported by other researchers [40,41].…”

Cost-effective assessment of filter media for treating stormwater runoff in LID facilities

“…한다 (Toraldo et al, 2013;Cabrera et al, 2014;Nguyen et al, 2015). 본 연구에 사용된 여재는 제올라이트(Zeolite, ZL), 우드칩(Woodchip, WC), 바텀애쉬(Bottom ash, BA), 바이오세라믹(Bioceramic, BC)등이다.…”

Adsorption of Pb(II) ions from aqueous solution using lignin from Hagenia abyssinica

“…Sources for environmental pollution can be natural processes like volcanoes or anthropogenic like industrial wastewater and the release of toxic compounds. Excessive levels of heavy metals in water are an environmental hazard because of their toxicity, accumulation in the food chain and persistence in nature [1][2][3]. Water contamination by heavy metals such as Cr, Cd, Hg, Cu, Ni, As and Pb, is a big environmental concern and it requires significant attention [4][5][6][7][8].…”