Total removal of heavy metal from mixed plating rinse wastewater

Abstract

A mixed plating rinse wastewater containing zinc, hexavalent chromium, trivalent chromium, and cyanide with total dissolved solids of 424 mg/1 was treated by a model consisting of a sand filter and ion exchange columns. A strongly acidic cation resin in hydrogen form and a strongly basic anion resin in hydroxide form were used in the columns as cationic and anionic exchangers, respectively. The cationic and anionic exchangers were regenerated by using 2% H2SO4 and 5% NaOH, respectively. A 100% removal of zinc, total chromium, hexavalent chromium and trivalent chromium was achieved in the studies. Very high removal of total dissolved solids, cyanide and hardness level was achieved at 98.9%, 99.9% and 96.5%, respectively. The conductivity of wastewater was reduced from an average of 358 μs/cm to 5 μs/cm. The case study has shown that treatment systems using cationic and anionic resin were able to treat a mixed plating bath effluent to comply with the standard discharge under the Malaysian Environmental Quality (Sewage and Industrial Effluents) Regulation, 1979.

Biofiltration: Essentials, Research and Applications

“…Commonly used matrices for ion exchange are synthetic organic ion exchange resins. Synthetic Dowex 2-X4 ion exchange resin was employed to remove the Cr (VI) from real plating wastewater [22]. The main disadvantage of the ion exchange method for heavy metal removal is that ion exchange resins are very selective.…”

Precipitation removal and recovery of Cr(VI) from aqueous solution under hydrothermal condition

“…The other treatments, ion exchange method 9) and electrochemical techniques, 10) have problems of cost and efficiency for chromium removal and recovering. Additionally, wastewater discharged from various industries containing broad range of Cr concentration.…”

EDTA excess Zn(II) back-titration in the presence of 4-(2-pyridylazo)-resorcinol indicator and naphthol green β as inert dye for determining Cr(III) as Cr(III)/EDTA complex: Application of the method to a leather industry wastewater

“…It enters the environment from industrial effluents or waste-disposal sources such as wastewaters from steel works, tanning and electroplating industries [3][4][5][6].…”

“…Various techniques as, for instance, precipitation with metal hydroxides, red-ox reactions, extraction, ion exchange chromatography, digestion, separation, adsorption, filtration and centrifugation can be used [3,[5][6][7][8][9][10][11]. The choice of the pre-concentration method will depend on the determination technique to be used and several pre-concentration systems implying different initial to final concentration ratios can be considered to perform volumetric analyses.…”