Surfactant-modified titania for cadmium removal and textile effluent treatment together being environmentally safe for seed germination and growth of Vigna radiata

Impact of Pollutant Load from Textile Dyeing Industry Wastewater on Biometric Growth Profile of Vigna radiata

The phytoremediation of wastewater has certain advantages, but the interactions of soil and crop properties have not been systematically studied. This study aimed to analyze how different concentrations of textile dyeing industry wastewater (25%, 50%, 75%, and 100%) affected soil qualities, growth, and yield attributes (Vigna radiata). In reaction to dyeing effluent at varying concentrations, the seed germination percentage, growth metrics such as tolerance index, phytotoxicity percentage, relative toxicity, extreme and plumule length were calculated. With increasing effluent concentrations, a gradual decrease in the germination of seed and seedling growth was observed. The maximal relative toxicity and percentage of phytotoxicity was 100%. Interaction of biometric growth profile relative seed germination, relative root growth, relative shoot growth, growth index, and seedling vigor index of V. radiata and physicochemical parameter of textile dyeing industry wastewater were also investigated by using the Pearson correlation co-efficient. Principal component analysis (PCA) is helped to obtain and recognize the factors/sources accountability of different concentrations of textile dyeing industry wastewater. The results of the PCA revealed that four components (PC1 to PC4) out of total principal components retained PC1, PC2, with values of 69.25% and 28.85%, respectively.

Solar light photocatalytic transformation of heptachlorobiphenyl (PCB 180) using g-C3N4 based magnetic porous photocatalyst

A novel porous core-shell magnetic β-cyclodextrin/graphitic carbon nitride photocatalyst (Mβ-CD/GCN) was synthesized and employed in a solar light driven catalytic system for the degradation of polychlorinated biphenyls (PCBs). The Mβ-CD/GCN display superior photocatalytic performance on account of porous structure and ultrathin GCN nanosheets design, the former improves the utilization of visible light by multiple scattering and reflection of incident light, and the latter accelerates electron transfer. The ultrahigh specific surface area (1255 m² g^-1) of Mβ-CD/GCN provided a large number of active sites for adsorption and degradation of the target pollution. The pseudo-first order reaction rate constant (k_obs) for the degradation of PCB180 by Mβ-CD/GCN was 0.021 min^-1, which improved 3.23 times than the bulk GCN. Additionally, the effects of various reaction parameters and water matrices were studied on the degradation of PCB180. Three possible degradation pathways and mechanism of PCB180 were speculated according to the identification of reaction intermediates and detection of reactive species. The solar light driven Mβ-CD/GCN catalytic technology is a promising method not only for the control of persistent organic pollutants (POPs), but also the catalyst could be recovered and reused through simple magnetic separation.

Effect of sewage sludge biochar on the soil nutrient, microbial abundance, and plant biomass: A sustainable approach towards mitigation of solid waste

Soils functions, fertility, and microbial abundance may alter in various ways by the biochar amendments to the soil. This study revealed the way of pyrolysis temperature influences the biochar quality and its addition for improving soil properties. The SS biochar was synthesized via pyrolysis and characterized by SEM and FTIR for studying surface images and chemical functional groups. The biochar upon addition with soil was studied for physiological parameters of plants like seed germination index, root length, shoot length, biomass, metal (loid) analysis of soil, SS and SS biochar, total organic content, C: N ratio, NPK values, etc. Besides, combinations of biochar: soil {1:3 (25% + 75%), 1:1 (50% + 50%), and 3:1 (75% + 25%)} ratios were used for studying the effect of biochar on soil microbial community. The 16S rRNA metagenomic analysis revealed the dominance of phyla: Proteobacteria, Actinobacteria, and Acidobacteria that influence the soil nutrient cycle when applied at ratio 1:3. This study highlights the valorization of SS into biochar and studied the effect of biochar augmentation with soil; its impact on soil nutrients, microbial abundance, and plant biomass enhancement. The greener approach also mitigates and helps in the sustainable management of solid wastes, thus reducing GHGs emissions and improves nutrient cycling.

Low levels of TiO2-nanoparticles interact antagonistically with Al and Pb alleviating their toxicity

The contamination and bioavailability of deleterious metals in arable soils significantly limits crop development and yield. Aiming at mitigating Pb- and Al-induced phytotoxicity, this work explores the use of P25 titanium dioxide nanoparticles (nTiO₂) in soil amendments. For that, Lactuca sativa L. plants were germinated and grown in the presence of 10 ppm Pb or 50 ppm Al, combined or not with 5 ppm nTiO₂. Growth parameters, as well as endpoints of the redox state [cell relative membrane permeability (RMP), thiobarbituric acid reactive substances content, total phenolic content and photosynthesis (sugars and pigments levels, chlorophyll a fluorescence and gas exchange), were evaluated. Concerning Al, nTiO₂ treatment alleviated the impairments induced in germination rate, seedling length, water content, RMP, stomatal conductance (g_s), intercellular CO₂ (C_i), and net CO₂ assimilation rate (P_N). It increased anthocyanins contents and effective efficiency of photosystem II (Φ_PSII). In Pb-exposed plants, nTiO₂ amendment mitigated the effects in RMP, P_N, g_s, and C_i. It also increased the pigment contents and the transpiration rate (E) comparatively to the control without nTiO₂. These results clearly highlight the high potential of low doses of nTiO₂ in alleviating metal phytotoxicity, particularly the one of Pb. Additionally, further research should explore the use of these nanoparticles in agricultural soil amendments.