Removal of Tin and Copper from Semiconductor Wastewater via Hydroxide Precipitation

The rapid growth of the semiconductor industry has led to increased water consumption in production processes, resulting in wastewater containing heavy metals such as tin (Sn) and copper (Cu), which must be treated before being discharged into the environment. This study aims to evaluate the effectiveness of chemical precipitation using sodium hydroxide (NaOH) in recovering Sn and Cu from the semiconductor wastewater. The NaOH concentrations of 1.0 M, 2.5 M, and 4.0 M were added to the wastewater and allowed to undergo mixing using flocculator. The resulting precipitate was analysed through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Field emission scanning electron microscopy with energy-dispersive X-ray (FESEM-EDX) spectroscopy to determine the functional groups, chemical composition and structure of the precipitate, respectively. The results indicated that 4.0 M NaOH was the optimum concentration for metal precipitation within 30 minutes, achieving 86.8% removal of Sn and 46.2% removal of Cu. FTIR analysis revealed that the precipitate contained metal–O2 stretching vibrations, while XRD confirmed the presence of tin hydroxide (Sn(OH)2). The precipitateexhibited a rough and textured morphology, characterized by small particles forming aggregates and fine fibrous networks. The precipitation method is a viable option for rapidly treating semiconductor wastewater to meet allowable discharge limits, thereby protecting the environment while enabling the industry to grow without causing significant ecological impacts.