Simultaneous reduction of copper and toxicity in semiconductor wastewater using protonated alginate beads

[Display omitted] •Cu was identified as a key toxicant in raw semiconductor wastewater.•Cu in raw wastewater was efficiently removed by protonated alginate beads.•Toxic unit values increased proportionally with Cu concentrations in effluent.•Daphnia magna was more sensitive toward Cu in effluent than other aquatic species. Using protonated alginate (HA) beads, copper (Cu2+) levels and toxicity were concurrently reduced in semiconductor wastewater produced from the chemical mechanical planarization process. The beneficial effect of protonation could be explained by a reduction in the release of Ca2+, which is a competitive cation during sorption of Cu2+, leading to an increased in the sorption capacity from 107 to 189mg/g. Monitoring of the acute toxicity of two different types of semiconductor wastewater toward Daphnia magna suggested that Cu2+ was the cause of toxicity. The toxicity identification evaluation using D. magna indicated that Cu2+ was a major toxicant in the raw wastewater with concentrations of 1.97 and 3.37mg/L for two different raw wastewater samples with initial toxicities of 14.2 and 23.6 toxic unit (TU), respectively. This relationship was verified by the correlation coefficients between Cu2+ concentration and acute toxicity (r2=0.829 at P