Abstract
ABSTRACT
Organic pollutants from semiconductor manufacturing pose significant threats to aquatic ecosystems and remain challenging to treat. To address these issues, mesoporous bio‐silica (diatomite) was employed as a platform material to accommodate titanium dioxide nanoparticles with oxygen vacancies (OVs) (TiO
2−
x
) and hydroxyl groups, which were synthesized and nano‐anchored via a rapid, low‐temperature (2−
x
nanolayer within the mesopores of bio‐silica. The resultant TiO
2−
x
nanolayer/bio‐silica composite (DE 700), with a low bandgap (2.68 eV) and a mixed anatase–rutile composition, achieved exceptional photocatalytic performance under a 300 W commercial solar lamp, degrading 20 ppm of tetramethylammonium hydroxide (TMAH), a highly toxic semiconductor wastewater pollutant, using a catalyst loading of 0.5 g/L. The catalyst achieved 62% TMAH conversion into ammonium ions with trace amine intermediates and complete TMAH degradation after 12 h of solar lamp exposure. It degraded 20 ppm methylene blue (MB) by 90% in 30 min and 100% in 120 min, significantly outperforming commercial TiO
2
‐P25, which achieved 29.22% TMAH removal and 14.11% ammonium ion conversion under same condition. Electrochemical impedance spectroscopy (EIS) and time‐resolved photoluminescence (TRPL) analyses indicated improved interfacial charge‐transfer kinetics and suppressed charge‐carrier recombination in DE 700 compared to TiO
2
‐P25. Additionally, the catalyst maintained 91%–97% degradation efficiency over four reused cycles, and a preliminary plant‐based sprouting assay indicated no observable phytotoxicity of the treated effluent, highlighting its potential as a cost‐effective solution for treating challenging feedwater streams.