Removal of some heavy metals from inorganic industrial wastewaters by ion exchange method

Removal of heavy metals such as Cu(II), Cd(II), Zn(II), Ni(Il) and Pb(II) from wastewaters in several industrial areas of Kerman, Iran was evaluated by using ion-exchange method. Dowex 50WX8 (H⁺) resin was selected as suitable adsorbent for reduction of toxic elements in wastewater. The most effective sorption was observed within in pH between 4 - 6, fow rate of 4mL min⁻¹ and amount of 200 mg resin. Sorbent capacities for Cu(II), Cd(II), Zn(II), Ni(II) and Pb(II) were 45; 50; 50; 40 and 60 mg/g respectively. The results determine that exchanger resin is extremely effective in lowering the metal content of wastewaters

Removal of Cadmium from the Leaching Solution Using Electrocoagulation

In the present study, the electrochemical coagulation process (electrocoagulation) in the mining industry was investigated in order to remove one of the heavy metals, cadmium, from the leaching solution of the copper processing plant. The response surface methodology (RSM) was used to optimize the factors affecting the removal of this metal in the electrocoagulation process. For this purpose, Behnken Box Designv(BBD)  was used to optimize the experiments. The effects of three independent parameters such as pH (X1), electrolysis time (X2), current density (X3) were investigated in order to investigate the removal of cadmium from the leaching solution. The quadratic model was used to respond to the cadmium removal efficiency. The most important independent variables and the interaction between them were evaluated using ANOVA test. This study showed that the optimal operating conditions for cadmium removal are 96.96% at initial pH: 6.83, electrolysis time: 116 min and current density: 69.262 A/m2. The results showed that the ability of electrocoagulation process can be considered as a reliable method to remove cadmium from industrial effluents, especially in mineral processing plants

Impact of anthropogenic activities on the chemistry and quality of groundwater: A case study from a terrain near Zarand City, Kerman Province, SE Iran

Groundwater of an aquifer located in the vicinity of a large coal washery near Zarand City, Iran consists of two hydrochemically differing facies, which have been informally designated as groundwater (A) and groundwater (B). Groundwater (A) is native, brackish in composition and is characterized by Na+ > Mg2+ > Ca2+ > K+ and SO4 2- > HCO3 - > Cl- > NO3 -. Spearman's rank correlation coefficient matrices, factor analysis data, and values of chloro-alkaline indices, C ratio and Na+/Cl- molar ratio indicate that in the groundwater (A), the ionic load of Ca2+, Mg2+, Na+, K+, SO4 2- and HCO3 - is derived essentially from weathering of both carbonates and aluminosilicates and direct cation and reverse cation-anion exchange reactions. Groundwater (B) is the polluted variant of the groundwater (A), brackish to saline in composition, and unlike the groundwater (A), consists of HCO3 - as the dominant anion. In comparison with the groundwater (A), the groundwater (B) contains higher concentrations of all ions, and its average ionic load (av. = 59.74 me/L) is 1.43 times higher than that of the groundwater (A) (av. = 41.54 me/L). Additional concentrations of Ca2+, Mg2+, K+, SO4 2-, Cl- and HCO3 - in the groundwater (B) are provided mainly by downward infiltrating water from the coal washery tailings pond and reverse cation-anion exchange reaction between tailings pond water and exchanger of the aquifer matrix during non-conservative mixing process of groundwater (A) and tailings pond water. Certain additional concentrations of Na+, K+ and NO3 - in the groundwater (B) are provided by other anthropogenic sources. Quality wise, both groundwaters are marginally suitable for cultivation of salt-tolerant crops only