Lanthanum/Iron Oxide Nanocomposite for Photo-Ultrafast Removal of Methyl Orange Dye and Toxicity Evaluation

: In the present investigation, a lanthanum/iron oxide nanocomposite was prepared and employed for the removal of methyl orange dye. The nanocomposite was prepared via a co-precipitation method. Lanthanum nitrate hexahydrate (La(NO3)3.6H2O) and iron nitrate hexahydrate (Fe(NO3)2.6H2O) were precursor salts. The prepared nanocomposite was characterized using XRD, SEM, FTIR, EDX and UV/Vis spectroscopy. The average particle size measured by Scherrer’s relation was in 15-20 nm range and particles showed the tendency of aggregates formation. The photocatalytic activity of the nanocomposite was evaluated against methyl orange (MO) dye (as a model organic pollutant) and up to 96% degradation of dye was achieved within 120 minutes of irradiation. The scavenging studies showed that •OH radical played a major role in MO dye degradation followed by h+ and e- species. The cytotoxicity of treated and untreated wastewater sample was evaluated by the Allium cepa assay. The root lengths and root count were recorded in the case of untreated, treated wastewater, positive control (methyl methanesulfonate) and negative control (distilled water) samples. The increase in root length and root count was observed to be 50% and 28.57% in the treated versus the untreated wastewater sample. The lanthanum/iron oxide nanocomposite also showed promising recyclability and reusability potential. The prepared lanthanum/iron oxide nanocomposite showed promising photocatalytic activity, which could have potential application for the remediation of dyes in the textile effluents.

Rubina Nawaz, Muhammad Asghar Jamal, Bushra Naseem, Majid Munir, Munawar Iqbal