Redox flow desalination for tetramethylammonium hydroxide removal and recovery from semiconductor wastewater

Redox-Mediated Electrodialysis for Desalination, Environmental Remediation, and Resource Recovery

“…Along with material selection, operating conditions play a crucial role in achieving an optimal performance. The redox-ED system can be operated at both constant voltage (0.4−1.2 V) 5,12,13,16,43 and current (0.1−2 mA cm −2 ). 9,17,22 Typically, constant voltage operation is advantageous for maximizing salt removal or its rate, whereas constant current operation is effective for optimizing energy consumption or selectivity.…”

“…System size exhibits considerable variation across the literature, with the electrode sizes ranging from 9 to 50 cm 2 , 5,12,13,16 flow rates from 0.5 to 11.6 mL min −1 , 9,17,22,61 and concentrations of redox couple between 4 and 200 mM. 5,12,13,17,22,43 The closedloop circulation�where a batch of the treating solution circulates over time � has been frequently adopted to achieve desalination down to potable water or the upconcentration of target species in resource recovery.…”

“…The disposal of industrial and urban wastes is recognized as a significant and ongoing issue in environmental pollution. Industrial wastewater contains anthropogenic chemicals 18,43,81,82 and toxic gases, 83,84 while large-scale agricultural activities release excess fertilizer runoff, exacerbating the ecological imbalance and posing threats to human health. 17,85,86 Consequently, there has been a growing emphasis on effective environmental remediation as a crucial research focus.…”

“…87−89 Additional treatment processes are often required to treat specific species, adding complexity to wastewater plants. In tackling these environmental challenges, redox-ED has been shown to effectively treat wastewater from diverse sources by employing proton-mediated redox species, 17 a specific solution media 43 or membrane, 17 and electrode modification. 16 This section delves into examples of wastewater treatment using the redoxmediated platform, encompassing agricultural, industrial, and municipal wastewater contexts.…”

“…Growing manufacturing sectors, such as electronic industries, further complicate wastewater treatment by introducing organic contaminants, heavy metals, and fluorinated compounds. 18,43,81,82 For example, the semiconductor and optoelectronic industries generate substantial volumes of TMAH-containing wastewater, as TMAH solution is essential for the etching process. 18,91,92 Traditional biological wastewater treatment methods are not suitable to treat TMAH, since it is detrimental to microorganisms present in the activated sludge.…”