Biomediated nanosized ZnS using Ulva fasciata and Citrus japonica: A new bio-photocatalyst for textile wastewater treatment

Abstract

The aquatic ecosystems face excessive stress and depletion due to many pollutants impacting water quality. Biosynthesis of nanoparticles (NPs) using the green route represents a cost-effectively and eco-friendly approach, with significant applicability in various fields. In this regard, ZnS-NPs with improved photocatalytic and antimicrobial activities were biosynthesized for the first time from Ulva fasciata and Citrus japonica aqueous extracts. Biosynthesized ZnS-NPs were characterized and compared with chemically synthesized ones using UV–Vis spectroscopy, FTIR, TEM, XRD, and EDAX. TEM micrographs and XRD confirmed the formation of polygonal and spherical-shaped ZnS blend sphalerite nanocrystals with an average diameter between 7 and 31 nm. The optical properties of the produced ZnS-NPs showed higher band-gap energy of 5.63 eV and 4.76 eV for chemically and biosynthesized ZnS-NPs, respectively, as compared to ZnS macromolecules (3.77 eV). Biosynthesized ZnS-NPs showed excellent photocatalytic activity toward textile wastewater and two organic dyes (crystal violet and safranin), with significant degradation efficiency of 82–96.8, 82.5–98.12, and 84–95.9%, respectively. Biosynthesized ZnS-NPs showed high stability up to three subsequent cycles of photodegradation and exhibited promising antimicrobial activity against different Gram-positive and Gram-negative bacteria and Candida albicans. Biosynthesized ZnS-NPs have a less cytotoxic effect (IC50 > 300 μg/mL) than chemically synthesized ZnS-NPs (IC50 88 μg/mL) on human skin fibroblast normal cell lines. The photocatalytic efficiency of the biosynthesized ZnS-NPs has some advantages, such as non-toxic products, cost-effectiveness, and antimicrobial activity, which give them superiority to be used as a safe bio-photocatalyst for water treatment. Graphical abstract

Post-harvest biocontrol of Fusarium infection in tomato fruits using bio-mediated selenium nanoparticles

“…The carboxyl group (C=O) stretching vibration peaks was detected at 1229.25 cm −1 (Satgurunathan et al 2017 ). Effective stabilizing and/or reducing agents in the bioextract are due to the existence of important functional groups, such as O–H, N–H, C–N, C–H, N–O, C–N–C, and C=O as previously proposed by Elnady et al ( 2022a , b ) that is probably responsible for the bio-reduction and stability of SeNPs.…”

“…The antimicrobial activity of SeNPs is probably attributed to reactive oxygen species (ROS), such as hydroxyl radicals, superoxide anions, and hydrogen peroxides. ROS induce damage to the microbial cell membrane, inhibiting the DNA replication and amino acid synthesis (Filipović et al 2021 ; Elnady et al 2022a , b ).…”

“…The low cytotoxic effect of biosynthesized SeNPs is probably due to several functional biomolecules found in the bio-extract used for biosynthesis and stabilization as confirmed by FTIR analysis, such as O–H, N–H, C–N, C–H, N–O, C–N–C, and C=O. Many researchers suggested that the cytotoxic effect of NPs depends on various factors, such as its administration routes, size, aggregation; time exposure and/or concentration, as well as capping agent used for the stabilization of produced NPs (Tayel et al 2017 ; Sorour et al 2019 ; Elnady et al 2022a , b ). Similarly, Elnady et al ( 2022b ) reported lower cytotoxicity on normal cell lines for bio-mediated AgNPs using Ulva fasciata and Citrus japonica bio-extracts as compared with chemically-synthetized ones.…”

“…The use of SeNPs has fewer toxicological concerns as compared to bulk Se (Khurana et al 2019 ). Importantly, NPs have been produced via eco-friendly techniques using microbial and plant sources (Elbaz et al 2016 ; Zambonino et al 2021 ; Elnady et al 2022a , b ). Green biosynthetic methods have been widely used to produce metallic NPs like gold, silver, zinc oxide, selenium, and others, because they are non-toxic, and compatible with many biomedical and food applications (Tayel et al 2017 ; Elnady et al 2022a , b ).…”