Assessment of an MnCe-GAC Treatment Process for Tetramethylammonium-Contaminated Wastewater from Optoelectronic Industries

Abstract

Nitrogen-containing wastewater is an important issue in optoelectronic and semiconductor industries. Wastewater containing nitrogen compounds such as ammonium, monoethanolamine (MEA), and tetramethylammonium hydroxide (TMAH) must be properly treated due to concerns about health and environmental effects. MnCe-GAC (granular activated carbon) processes were developed in this study for the treatment of TMAH-contaminated wastewater in high-tech industries. The MnCe-GAC processes could effectively remove ammonium, MEA, and TMAH from aqueous solutions. The removal efficiencies of ammonium and MEA by these processes were better than observed for TMAH. Parameters affecting TMAH removal such as type of process, type of wastewater (synthetic or real), pH, salts, and t-butanol were investigated. In general, removal efficiencies of TMAH by various processes were in the following order: MnCe-GAC/O3/H2O2 > MnCe-GAC/O3 > MnCe-GAC/H2O2 > MnCe-GAC > GAC. The negative effect of sulfate and nitrate on pollutant removal might be due to the salting-out effect. Based on t-butanol experiments, the main degradation mechanisms of TMAH by the MnCe-GAC/O3/H2O2 process likely involved hydroxyl radicals. The process proposed in this study could be an effective alternative method for the treatment of high-tech industrial wastewater to meet the new TMAH discharge limit.

Synergistic treatment of carbon dioxide and nitrogen-containing wastewater by electrochemical C-N coupling

“… 11 As listed in Table 2 , the N-containing wastewater was usually generated from industrial activities like fertilizer, stainless steel, or nuclear fuel production, which also emitted large amounts of CO 2 in fumes. 12 , 13 , 14 , 15 , 16 In addition, during the treatment process of N-containing sewages, N 2 could be simultaneously generated with CO 2 by the denitrifying bacteria, which also could be collected and used as an available N source in the C-N coupling process. Therefore, considering N and CO 2 pollutions are produced simultaneously in many scenarios, setting electrochemical C-N coupling treating plants at the pollution headstream could be a more efficient approach to achieving emission reductions and avoiding the potential hazards and costs caused by pollutant transportation.…”

Removal of Cu(II) from Aqueous Solutions Using Amine-Doped Polyacrylonitrile Fibers

“…When the concentrations of coexisting cations increased to 10 mM, the amounts of adsorbed Cu(II) were 92.80 and 92.26 mg/g, respectively. These increases in the adsorption capacity were due to the salting-out effect of NaCl and CaCl 2 [29,30], causing Cu(II) ions to move into the interface of the surface-modified PAN fiber. The adsorption capacity increased with increasing salt concentration, but there was no difference between types of salts at the same molar concentration.…”