Use of solvent extraction for the removal of heavy metals from liquid wastes

Abstract

Solvent extraction is recommended as a suitable method for the removal of heavy metals from the waste waters of the chemical and electronic industries. Common extractants are organic compounds with molecular mass 200-450, almost insoluble in water (5-50 ppm), that selectively extract metals from aqueous solutions. On the basis of data from the literature, the extraction conditions are reviewed for the metals that cause problems in waste waters. The extraction conditions are understood to mean the type of extractant, anion present in the aqueous phase, and pH. As far as the data permit, the metals are ordered according to their extractability by given extractants. Special attention is paid to the main source of contamination of waste waters by heavy metals, namely electroplating plants. Two examples of the design of mixer-settler batteries are presented, which demonstrate continuous removal of heavy metals from the waste waters of electroplating plants to levels below the permissible limits. The first example illustrates removal of cadmium using triisooctylamine in a mixer-settler battery with the pertraction flow-arrangement; the second, removal of zinc and lead from rinse waters using the organophosphoric acid DEHPA (bis (2-ethylhexyl) phosphoric acid) in a battery with counter-current flow and reflux. The extraction equilibrium data were obtained in laboratory experiments using chloride solutions in concentrations close to those in the rinse waters of electroplating plants (Černá and Volaufová, 1991).

Decontamination of Cr(VI) and Mn(II) from aqueous media by untreated and chemically treated banana peel: a comparative study

“…There are a number of techniques used for removal of heavy metals such as electrolysis, chemical precipitation, oxidation reduction, solvent extraction, ion exchange, and adsorption [7][8][9][10][11][12]. Adsorption paid great attention because of low-cost materials as adsorbent for the removal of heavy metals and organic pollutants from industrial wastewater.…”

Uptake of Cu2+and Zn2+from simulated wastewater using muskmelon peel biochar: Isotherm and kinetic studies

“…Several techniques available for heavy metals removal from wastewater such as reverse osmosis [1], electrocoagulation [2], ultrafiltration [3], dialysis/electrodialysis [4], and solvent extraction [5] are either costly or less effective due to their own limitations. However, the treatment of aqueous effluents using adsorption of metals onto low cost adsorbents [6][7][8][9][10][11][12] is regarded as an efficient and economical alternative.…”

Kinetic Study of Cd(II) Ions Extraction Using Trioctylamine as Carrier in Bulk Liquid Membrane (BLM)

“…Reported techniques are filtration, flocculation, biological processes, solvent extraction, ions exchange and precipitation. [3][4][5] However, these techniques have drawbacks as some of them are energy intensive process besides generating secondary and highly toxic sludge. In addition, they are costly as well as unable to gain high removal of the metal ions.…”