A deterministic mechanism for efficient removal of arsenic and lead from wastewater using rapidly synthesized TiO2-(α-Fe2O3) nanoshells

Abstract

Removal of heavy metals from wastewater using efficient techniques became demanding wherein various nanomaterials with tailored physicochemical traits can be useful. Thus, PLAL approach at an optimum laser energy was used to make TiO2-(α-Fe2O3) nanoshells (TFNSs) by mixing nanoparticles (NPs) suspension of TiO2NPs (TNPs) and α-Fe2O3NPs (FNPs) at 50 to 50 ratio. The produced nanocomposites were customized by targeting Ti that was submerged in deionized water as growth medium and then irradiate using the laser pulses with an optimum laser energy 10.6 J/cm2, spot focused size of 1.2 ± 0.2 mm, frequency of 6 Hz, and laser beam with a pulse duration of 8 ns for 15 minutes. In the course of the ablation process, the solution was agitated to achieve the formation of TNPs, FNPs, and TFNSs by preventing the formation of craters on the target surface. The obtained NSs were characterized to evaluate their structural, morphological, optical absorption and fluorescence characteristics. TEM micrographs of the liquid suspension confirmed the existence of spherical nanocrystallites of TiO2-(α-Fe2O3)NSs with mean diameter ≈12.4 ± 1.31 nm. XRD and FTIR results have been used to identify the samples crystalline nature and high purity. LSPR absorption bands of TFNSs were evidenced at 230 to 300 nm. These NSs showed prominent fluorescence peaks escorted with blue shift. Arsenic and lead removal efficiency of TFNSs from wastewater was better (over 99% at pH = 9) than TNPs and FNPs. The removal of arsenic and lead from wastewater by TNPs, FNPs and TFNSs were explained using a possible mechanism. The obtained results suggest that the proposed NSs can be potential for wastewater treatment, contributing towards sustainable growth.