Efficient photo-adsorptive eradication of endocrine disrupting pesticides by chitosan co- decorated metal oxide bio-nanocomposite

Abstract

Extensive consumption, toxicity, and bioaccumulation of malathion (MLT) and lindane (γ-HCH) pesticides collectively attract the world's attention. Herein, the nanocomposite of chitosan wrapped NiO@ZnO was synthesized by a green methodology using Azadirachta indica leaves extract. Structural and morphological analysis of chitosan-NiO@ZnO showed hollow sphere-ake shaped image adsorbed on a solid chitosan surface with a large surface area of 73 m 2 g -1 . A decrease in values of lattice strain, dislocation density and crystallite size described the imperfection in crystal geometry and new peaks in FT-IR spectra at 698 cm -1 and 448 cm -1 of Ni-N and Zn-N, respectively con rms the coupling. The chitosan-NiO@ZnO nanocomposite with a reduced band gap due to the generation of new energy levels in the vicinity of of conduction and valence band. Chitosan-NiO@ZnO and individuals nanoparticles (NiO and ZnO) were well-characterized and utilized for degradation MLT and γ-HCH under direct sunlight and dark conditions. The highest degradation of pesticides (above 94%) resulted with 2 mg L -1 and 10 mg L -1 of MLT (π_π) and γ-HCH, respectively with a 20 mg catalyst dose, and pH of ~7 under daylight exposure (5 h). Chitosan-NiO@ZnO substantially suppressed the half-life of the targeted pesticides (MLT: 0.48 h; HCH 0.51 h) and demonstrated the rst-order kinetics with a high adsorption capacity, X m (MLT: 14.5 mg g -1 and γ-HCH 20.7 mg g -1 ), which also con rmed the strong binding with the pesticides, followed by their conversion into safer and smaller metabolites. The charge separation mechanism was elucidated by UV re ectance and photoluminescence data. Hydroxyl radicals were most frequently responsible for the degradation of pesticides as con rmed by scavenger analysis. The synthesized green-nano photocatalyst showed high reusability (up to 10 th cycles), sensitivity, and stability within the degradation process, presumably making it suitable for industrial applications.

Highly Efficient Photocatalytic Remediation of Carcinogenic Anthracene and Phenanthrene by green Synthesized N‐doped Prussian blue Analogues

“…Moisture presence was seen in a broad band at 3400 cm −1 (−OH stretching), and bending bands at 1610 cm −1 in MHCF samples. The C−N stretching observed at 2173 cm −1 , while Fe−N peak at 441 cm −1 , and 604 cm −1 (Fe−C bond vibration) [36] . Similar peaks were observed in synthesized two N−MHCFs.…”

“…The CÀ N stretching observed at 2173 cm À 1 , while FeÀ N peak at 441 cm À 1 , and 604 cm À 1 (FeÀ C bond vibration). [36] Similar peaks were observed in synthesized two NÀ MHCFs. The Metal-N bond was found at 585 cm À 1 (CuÀ N) and 580 cm À 1 (ZnÀ N) (Figure 1S).…”

A Review on the Use of Metal Oxide-Based Nanocomposites for the Remediation of Organics-Contaminated Water via Photocatalysis: Fundamentals, Bibliometric Study and Recent Advances

“…Table 1 shows some of the most recent research works on the use of mixed MO for the degradation of antibiotics and pesticides in water. Atrazine herbicide/50 mg L −1 / 100% in 60 min/5 cycles reuse [138] NiO/ZnO heterostructures embedded in the chitosan pores Sunlight/ 30 mg Malathion insecticide/20 mg L −1 / 94% in 5 h/5 cycles reuse [139] n.i.-no information.…”

Green synthesis of silver‐doped metal hexacyanoferrates nanostructures for efficient cleanup of endocrine‐disrupting pesticides

“…Because of environmental concerns and the implication of green chemistry, there is the trend for the synthesis of doped nanoparticles using plant feedstock (plants, roots, flowers, leaves) which contain several types of phytochemicals such as polyphenols, cellulose, saponins, sugars, flavonoids, and amino acids. [25][26][27][28][29][30][31] Therefore, it was envisioned to synthesize silver-doped metal hexacyanoferrates (Ag@MHCFs) via the green route. Numerous publications indicated that MHCFs complexes have superior adsorption and catalytic properties because of their inherent features, including electrochemical and spectral properties.…”