Borosilicate glass-ceramic robust with traces zirconium and titanium for removing chromium (VI), synthesis, characterization

This study demonstrates that borosilicate doped with trace amounts of titanium and zirconium (BSZT) serves as an innovative alternative (mock-up laboratory borosilicate glassware) and marks a significant advancement in chromium removal technology. While the manufacturing of borosilicate glass-ceramic (active for Cr(VI) adsorption) typically requires temperatures of 1500 °C, BSZT can be processed effectively at a lower temperature of 900 °C. This reduction in processing temperature is made possible by using sodium metasilicate as a flux and enhancing the silicate content. The composition consists of silica maintained below 84%, borate at approximately 8%, with titanium and zirconium collectively representing 8% weight by weight. To assess the adsorption and desorption properties of this material, various experiments were conducted, altering parameters such as solution pH, contact time, borosilicate weight, and chromium concentration. Advanced characterization techniques—including FTIR, SEM, EDS, and BET—were utilized to evaluate the modified borosilicate’s morphology, bonding, and surface characteristics. Impressively, the modified borosilicate achieved a chromium adsorption efficiency of 65% with an uptake capacity of 25 mg/g in just 30 s. Adsorption isotherm studies indicated that chromium ions adhere more closely to the Langmuir model than to the Freundlich model. Kinetic analyses further confirmed that the adsorption process is chemically driven and aligns with the pseudo-second-order model.