Fabrication of 3D lignosulfonate composited sponges impregnated by BiVO4/polyaniline/Ag ternary photocatalyst for synergistic adsorption-photodegradation of fluoroquinolones in water

In this work, a 3D lignosulfonate composited poly(vinyl formal) (PVF) sponge impregnated by BiVO4/polyaniline (PANI)/Ag ternary photocatalyst (PLS-BiVO4/PANI/Ag) was designed and fabricated. The synergistic adsorption-photodegradation of five fluoroquinolones (FQs) antibiotics onto PLS-BiVO4/PANI/Ag was investigated. Incorporating lignosulfonate as a carrier on PVF sponge improved its structural properties and enhanced its adsorption performance toward FQs. The BiVO4/PANI/Ag ternary photocatalyst was well-dispersed and tightly bound to the composited sponge, thus it efficiently degraded the adsorbed FQs through surface photodegradation. PLS-BiVO4/PANI/Ag achieved \u3e90% removal efficiency for all examined FQs within 2.0 h in a batch system, while it maintained a steady 80% removal efficiency for 30.0 h in a continuous dynamic treatment system. Photoelectric characterizations and ESR results showed that BiVO4/PANI/Ag was consistent with the type II heterostructure and effectively improved the utilization of visible light and the separation of photogenerated electron-hole pairs. The hole was the dominant active species in the degradation of FQs, while the main degradation pathways included defluorination, decarboxylation and destruction of piperazine ring. The prepared composited sponge is thus characterized by its high performance, convenient operation, eco-friendliness, and practicality in real water treatment systems since it undergoes self-purification and is easily recovered from water without mass loss

Environmentally safe biopolymer-clay composite for efficient adsorption of ciprofloxacin in fresh and saline solutions

In alignment with the sustainable development goals (SDGs), recent trends in water management have been directed toward using environmentally friendly bio-based materials for removing contaminants. In this work, we prepared a biocomposite of chitosan (CS) intercalated into acid activated calcium bentonite (Bent). A thermally stable mesoporous CS-Bent composite was prepared with a zeta potential of 15.5 to −34.4 mV in the pH range of 2.22–10. The biocomposite successfully removed up to 99.2% and 50 mg/g of the antibiotic ciprofloxacin HCl (CPX) at pH 5.5 via electrostatic and hydrogen bonding forces. In a multi-component aqueous system of heavy metal and CPX, the composite was more selective to CPX than to the heavy metals and removal of CPX in this system was comparable to that in a single-component system. The composite also maintained its high adsorption efficiency in NaCl solutions which makes it suitable for treating fresh and saline solutions. The combination of CS and bent produced a biodegradable eco-friendly composite characterized with good thermal and surface properties along with efficient and selective adsorption performance

Nano-formulations of copper species coated with sulfated polysaccharide extracts and assessment of their phytotoxicity on wheat (Triticum aestivum L.) seedlings in seed germination, foliar and soil applications

© 2020 by the authors. Copper nanoparticles were synthesized via a bioreduction using sulfated polysaccharides (SPs) extracted from Avicennia marina mangrove leaves and their phytotoxicity effect on wheat (Triticum aestivum L.) seedlings was assessed. As analyzed by high-performance liquid chromatography (HPLC), SPs extract constituted mainly 49.3% glucose, 24.6% galactose and 20.5% glucouronic acid by mol. A nanoformulation of ultrafine Cu2O/Cu(OH)2 nanoparticles coated with SPs (Cu NPs) was prepared with an average particle size of 2.11 ± 0.64 nm and a slightly negatively-charged zeta potential of 11 ± 0.46 mV. Applying high concentrations of Cu NPs on wheat seeds inhibited the respective shoot and root relative growth percentages, yielding 13.22 ± 9.91 and 36.72 ± 18.51% at 0.06 mg/mL of the nanoformulation. Comparable values were obtained when the seeds were subjected to 0.06 mg/L of SPs extract applied in the free form. In a foliar application, 0.06 mg/mL of Cu NPs reduced the respective total chlorophyll and carotenoids contents by 17.4% and 24.3% relative to the control while the treatment with SPs reduced them by slightly higher values of 27.9% and 32.6%, respectively, after 14 days of application. Therefore, Cu NPs show a comparable inhibition effect to that of the free SPs extract but offer the additional advantages of nanoformulations. In soil applications, however, Cu NPs stimulated the growth of wheat seedlings in contrary to SPs and increased the total chlorophyll and carotenoids by 49.76% and 70%, respectively. This gives an additional merit to the nanoformulation that can potentially be used as an effective biostimulant in soil

Seasonal dynamics and ecological risks of organochlorine pesticides in Kafrelsheikh-Egypt: Implications for aquatic ecosystems and public health

Kafrelsheikh, situated in the middle of the Nile Delta, significantly contributes to Egypt's aquaculture and agriculture sectors. However, the local use of organochlorine pesticides (OCPs) in agriculture is often a source of OCP residues in associated drainage waters, which may threaten aquatic ecosystems. These pesticides persist in local water bodies, jeopardizing aquatic ecosystems and potentially impacting human health. This comprehensive study assessed the seasonal variations of 17 OCPs in both water sources and Nile tilapia across eight fish farming locations in Kafrelsheikh. Using gas chromatography coupled with mass spectrometry (GC-MS), we detected OCP concentrations in water that varied seasonally where winter recorded the highest levels at 22.5 ng/mL and, summer showed the lowest levels at 6.2 ng/mL. Despite water samples occasionally showing risk quotients (RQs) greater than 1, indicating a potential threat to aquatic life, the OCP levels in Nile tilapia were sufficiently low, with target hazard quotients (THQ) below 1, suggesting no significant risk for human consumption. The research highlights a pressing need for regular environmental monitoring and stricter regulatory control over pesticide use to protect aquatic life and ensure the safety of aquaculture products. These findings provide a critical basis for policy-making, aimed at balancing agricultural productivity with environmental sustainability in regions heavily dependent on both