Abstract:
The paper presents studies on the removal of copper from wastewaters with high copper ions content resulting from galvanizing process. In the first step of the purification process, copper ions were precipitated using a 10 M NaOH solution as precipitation agent. By increasing the pH of the Cu(II) solutions up to 12, the residual concentration of copper ions reached the values required for the discharge in sewerage and in water resources. Taking into account that this pH value does not allow the discharge, the solution resulting from the precipitation process at pH 8 was submitted in the second step to an advanced treatment using as adsorbent material an Amberlite XAD-7 resin impregnated with di-2(ethyl-hexyl) phosphoric acid. To establish the conditions for the adsorption process was studied the influence of contact time and of adsorbent dosage on the efficiency of copper ions removal from the solution. The maximum efficiency of ~ 98% was reached after 90 min for an adsorbent dosage of 0.3g:25 mL. The residual concentration of copper ions was ~0.1 mg/L, value that allows the discharge in the sewerage and even in water resources.
Keywords:
copper, wastewater, XAD-7, impregnated resin, adsorption, DEHPA
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