Remediation of zinc metal from electroplating wastewater using biogenic hydrogen sulfide technology

Date

2011

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Pauline Angelic T. Roxas

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Abstract

In this study, the biogenic hydrogen sulfide technology was employed in treating electroplating wastewater containing zinc. Synthetic wastewater containing analytical grade zinc sulfate pentahydrate solids were used in the optimization procedure. The hydroxide precipitation was observed experimentally to eliminate the pH at which zinc hydroxide precipitation occurs, as this could interfere with ZnS precipitation. In the optimization of pH, solutions with pH 1-6 were subjected to biogenic hydrogen sulfide technology. The optimum pH obtained is pH 6 resulting in 87.28 % ZnS precipitation and a residual concentration of 14.04 ppm. To determine the maximum amount of zinc that could be removed for a given concentration after hydrogen sulfide treatment, the concentration was optimized using 100, 500, 1000, 2000, 3000 and 5000 ppm. These results showed that the biogenic hydrogen sulfide technology is highly efficient in treating zinc-containing wastewater up to 5000 ppm and lowering the residual concentrations of each to the acceptable level of zinc in industries. Treatment of actual electroplating wastewater obtained from an electroplating company in Laguna, Philippines was performed. The initial concentration, pH and conductivity of the actual electroplating wastewater were found to be 476.24 ppm, 6.68 and 2.22 mS/cm, respectively. The concentration of zinc in the electroplating wastewater decreased to 6.88 ppm after treatment with biogenic hydrogen sulfide technology. This accounts for the 98.56 % ZnS precipitation. Cost analysis for biogenic hydrogen sulfide technology was done to estimate its economic feasibility. It was found that 200 mL of wastewater containing up to 5000 ppm can be treated by biogenic hydrogen sulfide technology and lower its effluent up to 98.14 % zinc sulfide precipitation for only Php 66.02.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Document Type

Thesis

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