폐자원 재활용 흡착제를 이용한 도금폐수 내 중금속 제거

Abstract

The objective of this study was to remove heavy metals (Cr, Fe, Cu, and Zn) from plating wastewater (PWI and PWII) by using waste-reclaimed adsorbent. The physical and chemical characteristics of waste-reclaimed adsorbent was analyzed by XRD, SEM, BET and pHpzc. The possible species distribution of heavy metals depended on the solution pH was predicted by VMINTEQ software program. The experiments using jar-tester showed that the removals of Cr, Fe and Cu were similar when either NaOH or adsorbents (L-type adsorbent and H-type adsorbent) were used. However, the higher removal of Zn was observed when adsorbents were used. This could indicate that Zn was removed more efficiently by adsorption than by coagulation or precipitation. Because of the loss of adsorbent in jar-tester and the high removal efficiency of adsorbents, adsorption was tested by the packed-bed reactor. As results, Cu was adsorbed more likely on H-type adsorbent than L-type adsorbent. This could be explained by the correlation between the surface charge of adsorbent and the solution pH. The point of zero charge of H-type adsorbent was 6.7. Therefore, H-type adsorbent was more negatively charged than L-type adsorbent. In addition, duel treatment system for plating wastewater could be contained both adsorption process (i.e. packed with waste-reclaimed adsorbent) and advanced oxidation process. Reuse test was repeated for 40 times, and the removal efficiency of Cr, Fe, Cu and Zn was 75%, 99%, 97% and 96%, respectively.

Keywords: heavy metal, waste-reclaimed adsorbent, pHPZC, reuse