Photolytic and Photocatalytic activity of polyethylene glycol capped zinc ferrite nanocomposite to the removal of sethoxydim herbicide residues in pond water

Nageswara Rao Tentu¹Ramaraju K²Prashanthi Yarasani²Parameswaram Ganji^3*

• ¹Isosphere Biosciences Pvt Ltd, Secundrabad, India
• ²Mahatma Gandhi University, Nalgonda, India
• ³Institut Jozef Stefan, Ljubljana, Slovenia

Zinc ferrite nanoparticles were produced using the sol-gel method, with precursors like zinc nitrate and iron nitrate. The solution was magnetically stirred, subsequently dried, and annealed. A clear PEG solution was formed by dissolving 1g of PEG in distilled water. The PEG-ZnFe2O4 nanocomposites were synthesized by heating and calcining the mixture at 300°C for 3 hours. Polyethylene glycol capped zinc ferrite nanocomposites (PEG-ZnFe2O4 NCs) are characterized using various methods such as TEM, SEM, FT-IR, UV-Vis spectroscopy and XRD. These techniques provide detailed descriptions of the NCs morphology, size distribution, functional groups, crystalline structure and phase composition. The uniform concentrations were established as follows: T0 – Untreated Control, T1 – sethoxydim 12.5% EC at 1 µg/mL. These concentrations were introduced to carry out photolytic and photocatalytic studies of alkane residues in water, both with and without a nanocatalyst. Replications were performed at each fortification level, along with control samples for comparison. Two sets of spiked concentrations were prepared for the experiments. One set of samples included the catalyst (PEG-ZnFe2O4), while the other set was tested without it. The samples were exposed directly to sunlight. Aliquots of the sample were collected at predetermined intervals. Water samples were collected throughout the duration, with temperatures ranging from 28 to 44°C. A 0.45 µm PTFE membrane filter was used to filter the samples collected at various sampling times. The filtrates were subsequently collected into amber-colored vials prior to validated HPLC method. The method validation process involved analyzing untreated control samples of pond water extract, acetonitrile, 0.1% ortho-phosphoric acid, working standard, and test solutions for method specificity. The calibration solutions were analyzed using HPLC at various concentrations. The fortified samples were analyzed using the HPLC method to extract and quantify sethoxydim in pond water. The limit of quantification (LOQ) was established by performing five injections of recovery samples at a fortification level of 0.03 µg/mL for sethoxydim for low-level recovery.