Recovery of Cu(II) by chemical reduction using sodium dithionite: effect of pH and ligands

Abstract

Wastewaters containing Cu(II) and ligands are ubiquitous in various industrial sectors, and efficacy of copper removal processes, especially precipitation, is greatly compromised by ligands. Chemical reduction, being commonly employed for production of metal nanoparticles, is also effective for metal removal. Adjustment of pH and addition of ligands are important to control the particle size in metallic nanoparticle production. Exploiting the fact that ligands and metals coexist in many wastewaters, chemical reduction was employed to treat ligand-containing wastewater in this study. The experimental result shows that depending on pH, type of ligands, and copper:ligand molar ratio, copper could be removed by either the reduction or precipitation mechanism. Almost complete copper removal could be achieved by the reduction mechanism under optimal condition for solutions containing either EDTA (ethylenediaminetetraacetic acid) or citrate ligands. For solutions containing ammonia, depending on pH and Cu:ammonia molar ratio, copper was removed by both precipitation and reduction mechanisms. At pH of 9.0, formation of nano-sized particles, which readily pass through a 0.45 μm filter used for sample pretreatment before residual copper analysis, results in the lowest copper removal efficiency. Both cuprous oxide and metallic copper are identified in the solids produced, and the possible explanations are provided.

Study of the Reduction Process of Iron in Leachate From Nickel Mining Waste

“…Bisulfite anion will reduce Fe(III) to Fe(II). The reaction between sodium dithionite and Fe(III) is presented in Equation 3 (Cermak and Smutek, 1975;Irwin, 2011;Chou et al, 2015;Luz and Lins, 2008 (1)…”

Separação Seletiva De Cobre Do Lixiviado De Níquel Laterítico Por Precipitação Utilizando Ditionito De Sódio

“…Outros trabalhos mostraram a viabilidade técnica da remoção de cobre utilizando ditionito de sódio [24][25][26][27]. Por esta razão, o objetivo deste trabalho é estudar o efeito da agitação e do tempo para a separação de cobre de solução de níquel laterítico.…”

“…Estudo cinético mostrou que a precipitação do cobre atinge 97% após 45min de reação. Em estudos realizados por Chou et al [24], a precipitação de cobre utilizando ditionito foi cerca de 100% em apenas 2min. Além do fato de a precipitação do cobre depender do valor de pH [24,26], a solução estudada era uma solução monoelementar, isto é, havia apenas cobre em solução.…”

“…Em estudos realizados por Chou et al [24], a precipitação de cobre utilizando ditionito foi cerca de 100% em apenas 2min. Além do fato de a precipitação do cobre depender do valor de pH [24,26], a solução estudada era uma solução monoelementar, isto é, havia apenas cobre em solução. Outros metais em solução diminuem a eficiência do processo e mais agente redutor é necessário para que o cobre presente em solução precipite.…”

Efficient ZIF-67 alginate composite hydrogel material and its application to enhanced copper (II) adsorption from aqueous solutions

“…Frequently, copper accumulated in the liver is one of the key reasons for symptoms such as headache, nausea, anemia, renal and liver failure, stomach bleeding, and death [6,7]. A variety of treatment technologies have been applied for the removal of ion Cu(II) including chemical precipitation [8,9], ion exchange [ 10 , 11 ], membrane filtration [ 12 ], coagulation-flocculation [ 13 ], flotation [14], and adsorption [15], among which adsorption is considered among the most feasible techniques due to its reproducibility, economy, ease of operation, effectiveness, and sensitivity to toxic substances [ 16 , 17 ]. It is an interesting but still challenging task to develop a specific adsorbent with high capacity and low cost.…”