Photocatalytic fuel cell is considered as a sustainable wastewater treatment system which could degrade organic pollutants and generate electricity simultaneously. In this study, a single-chambered photocatalytic fuel cell based on immobilized ZnO/Zn photoanode was evaluated under sunlight and UV light irradiation, respectively. Methylene blue was used as the dye pollutant in the photocatalytic fuel cell. The fabricated ZnO/Zn photoanode was characterized using scanning electron microscopy and X-ray diffraction. Significant difference in degradation efficiency of methylene blue was observed under UV and sunlight irradiation, respectively. Results showed that the decolorization efficiency and electricity generation of methylene blue in PFC and photolysis were higher under sunlight irradiation compared to those of the UV light irradiation. The decolorization trend of methylene blue was unstable under photolysis using UV light irradiation. Under sunlight irradiation, about 85% of methylene blue was decolorized by PFC, but only 35% of decolorization was observed under UV light irradiation. The maximum power density of the PFC under sunlight irradiation (0.0032 mW/cm²) was almost two times of that under the UV light irradiation (0.0017 mW/cm²).

This study was carried out to comparatively evaluate the bioaccumulation potency of Zn bulk and nanoparticles in Oreochromis niloticus and to investigate the induced hematological and histological alterations. Fish were exposed to ½ LC50/96 h values of both bulk and nano Zn meal for 7, 14, and 28 days. Concerning metal bioaccumulation factor (BAF), the data displayed that zinc nanoparticles (Zn NPs) had more efficiency to penetrate the studied tissues such as the liver, kidneys, gills, skin, and muscle. Hematological parameters named red blood cells (RBC), hemoglobin (Hb), and hematocrit (Hct) values were altered in Zn NPs treated groups after 14th and 28th days while these hematological parameters recovered to some extent in bulk particles (BPs) treated groups at the end of the experimental period. The changes in hematological parameters were found to be time dependent. Blood indices such as mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) revealed the presence of normocytic normochromic anemia in the studied groups at the most exposure periods except microcytic hypochromic anemia at the 7th day of bulk particles exposed fish. Based on histological end points, several alterations in the gills, liver, and kidney tissues were observed. Severely deformations were observed at NPs treated fish groups which varied between adaptive changes to tissue damage at the end of exposure period. The deformations were recorded to be increased in NPs exposed fish compared to BPs treated fish throughout the study periods.

Over the last few decades, the concentration of cadmium (Cd) in the environment has increased considerably in many countries due to anthropogenic activities. Cd is one of the most toxic pollutants in the environment and affects many metabolic processes in plants. The main objective of this study was to evaluate the response of the production, nutritional, and enzymatic antioxidant system of two tomato genotypes (Calabash Rouge and CNPH 0082) grown in tropical soils that were treated with doses of Cd. Soil samples were collected from the layer of earth at a depth of 0–0.2 m in areas subjected to a minimum of human disturbance. The concentrations of Cd applied to the soil samples were 0, 1, 2, and 4 times (0, 3, 6, and 12 mg kg⁻¹ of Cd) the agricultural intervention value adopted by current environmental legislation in the state of São Paulo, Brazil. Analysis of superoxide dismutase, catalase, glutathione reductase, guaiacol peroxidase, and ascorbate peroxidase activities, formation of stress indicator compound (malondialdehyde—MDA and hydrogen peroxide), parameters of production—dry mass of the shoot and root system (here in after “shoots” and “roots”), as well as nutrition, and both the bioavailable and total levels of this metal in the soil were performed. When the bioavailable content and total levels of Cd in the soil increased as a result of this metal doses applied, the biomass of both shoots and roots decreased in both genotypes (with the exception of the CNPH 0082 grown in clay soil) and displayed lower SPAD (relative chlorophyll index) values when exposed to contaminated environments with Cd concentrations. Cadmium treatment resulted in nutritional imbalances, mainly in terms of N, P, and Mn metabolism. Plants subjected to an elevated available content of metal in the soil exhibited increases in content of MDA and hydrogen peroxide and increased activity of catalase, ascorbate peroxidase, and guaiacol peroxidase in plant tissues when grown in both clay soil and sandy soil. Cadmium was phytotoxic to the plants causing a nutritional imbalance, especially on the metabolisms of N, P, and Mn. An oxidative stress condition was established in response to the Cd treatments applied, which led to changes in peroxidase activity.

Bombyx mori L. (B. mori) were exposed to cadmium chloride (CdCl₂) incorporated in an artificial diet (0, 6.25, 12.5, 25, and 50 mg kg⁻¹) throughout the larval stage. Changes in malondialdehyde (MDA) and reduced glutathione (GSH) contents and activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px), as well as their corresponding messenger RNA (mRNA) levels in the testes of the fifth instar larvae were evaluated. Additionally, spermatozoon deformation in the testes was examined. Upon Cd treatment, the MDA content in the testes was significantly increased in a concentration-dependent manner. Cd-exposed larvae had increased levels of glutathione. Pearson’s correlation analysis revealed that SOD and CAT activities were positively correlated (R ² = 0.605, P = 0.017). The changing trends in the mRNA levels of these enzymes were not always consistent with those of enzymatic activities. Alterations in GSH-Px activities and mRNA levels were positively correlated (R ² = 0.771, P < 0.01). Morphological analysis revealed that Cd deformed and affected the maturation of spermatozoa. Our results collectively support a relationship between Cd and alterations in the levels of antioxidant enzymes in B. mori testes.

The Platanus fruit fibers (PFFs) with unique hollow tubular structures were successfully utilized in the preparation of an efficient oil sorbents for the first time by chemical modification with acetic anhydride. The structure and morphology of the pristine PFFs (p-PFFs) and acetylated PFFs (a-PFFs) were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effects of acetic anhydride to PFFs ratio, catalyst concentration, reaction temperature, and time on the weight percent gain (WPG) and oil sorption capacity were particularly investigated in detail. The results showed the hydrophobic modification of p-PFFs contributed to the enhancement of the sorption capacity of a-PFFs for various oils and organic solvents. The sorption kinetic analysis indicated the oil sorption data were fitted well with a pseudo-second-order kinetic model. And the oil-filled a-PFFs exhibited high oil retention ability with less than 30 % of the sorbed oil lost after 2-h dripping. Moreover, a-PFFs showed little loss of initial sorption capacities after eight sorbing/desorbing cycles with the recovery of sorbents by n-hexane extraction. The natural renewable a-PFFs are proved to be a promising candidate for large-scale removal of spilled oils from water.

This study tested the efficacy of Zn-Al sulphate layered double hydroxides (LDH) as sorbent to remove antimony from circum-neutral solutions. Results of experimentation showed that Sb(V) in the anionic form Sb(OH)₆ ⁻ can be efficiently removed from aqueous solutions through an exchange process with the SO₄ ²⁻ present in the interlayer; total removal can be achieved within 6–24 h for A ≥2, where A is the ratio of the maximum theoretical anion exchange capacity (AEC) to the initial Sb concentration, both expressed in milliequivalents per liter. The complex rearrangement of the LDH structure to host Sb(OH)₆ ⁻ in the interlayer is correlated to an initial fast removal of the contaminant, followed by a progressive slowing down of the exchange process. The overall speed of the process is again a direct function of A; in practice, the sorbent dose should be carefully evaluated to balance cost/efficacy/timing of the water treatment. Comparison with previous studies documenting Zn-Al sulphate LDH efficacy as arsenate and molybdate sorbent indicates a comparable affinity for As(V) and Sb(V), higher than for Mo(VI). The results of this study reinforce the possible key role of Zn-Al sulphate LDHs in water treatment for pH ranging from circum-neutral to moderately alkaline, thanks to their capability to rearrange the original structure in order to host different-sized/charged anions.

An experimental study was performed to determine the feasibility of using physically treated Candida tropicalis cells for sorption of Cu(II) and phenol, the role of competition between phenol molecules and Cu(II). The yeast cells were lyophilized (LC), heat-treated at 65 °C for 24 h (HT1), at 90 °C for 24 h (HT2), and 72 h (HT3), inactivated at 120 °C and 104 kPa for 20 min (PC). The adsorption isotherms were determined in batch system. Experimental equilibrium data were evaluated using Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models by linear and non-linear regression. The adsorbed Cu(II) and phenol amounts by yeast cells were decreased due to the physical treatments of cells. With the increase of biomass dosage from 1 to 10 g L⁻¹, the adsorption efficiency was increased. The Cu(II) adsorption capacity was also determined in the presence of phenol at various initial concentrations, and in these systems, phenol adsorption isotherms were determined. In the presence of phenol, the Cu(II) sorption capacity by lyophilized cells and carbon particles was decreased. The most commonly used sorbent in water treatment is activated carbon with large specific surface; therefore, the results were compared with the experimental data obtained by using activated carbon (AC).

Mining activities can cause drastic disturbances in soil properties, which adversely affect the nutrient cycling and soil environment. As a result, many efforts have been made to explore suitable reclamation strategies that can be applied to accelerate ecology restoration. In this study, we reconstructed mine soils with fly ash, gangue, sludge, planted ryegrass, and inoculated arbuscular mycorrhizal fungi (AMF) in Pangzhuang mine of Xuzhou during 2009 to 2015. The soil aggregation process, enzyme activities (i.e., invertase, urease and acid phosphatase activities), soil organic carbon (SOC) as well as other soil nutrients such as nitrogen, phosphorus, and potassium contents of the reconstructed mine soils were monitored during 6-year reclamation. The integrated application of sludge and AMF led to a promising reclamation performance of mining areas, in which soil aggregate stability, enzyme activities, SOC, and ryegrass biomass were effectively enhanced. The micro-aggregates (< 0.25 mm) decreased with the increase of macro-aggregates (> 0.25 mm) during the reclamation, indicating that macro-aggregates were gradually formed from micro-aggregates during the pedogenesis of reconstructed mine soils. The correlation analysis shows that SOC contents in aggregate fraction of 0.25∼0.5 mm were correlated with aggregate distribution and enzyme activities. Enzyme activities, however, were not significantly correlated with aggregate distribution. The outcomes from the present study could enrich our understanding on soil property changes in pedogenesis process of reconstructed mine soils, and meanwhile, the employment of sludge combined with AMF is suggested to be an effective alternative for the mine soil reclamation.

Pesticides are used for controlling the development of various pests in agricultural crops worldwide. Despite their agricultural benefits, pesticides are often considered a serious threat to the environment because of their persistent nature and the anomalies they create. Hence removal of such pesticides from the environment is a topic of interest for the researchers nowadays. During the recent years, use of biological resources to degrade or remove pesticides has emerged as a powerful tool for their in situ degradation and remediation. Fungi are among such bioresources that have been widely characterized and applied for biodegradation and bioremediation of pesticides. This review article presents the perspectives of using fungi for biodegradation and bioremediation of pesticides in liquid and soil media. This review clearly indicates that fungal isolates are an effective bioresource to degrade different pesticides including lindane, methamidophos, endosulfan, chlorpyrifos, atrazine, cypermethrin, dieldrin, methyl parathion, heptachlor, etc. However, rate of fungal degradation of pesticides depends on soil moisture content, nutrient availability, pH, temperature, oxygen level, etc. Fungal strains were found to harbor different processes including hydroxylation, demethylation, dechlorination, dioxygenation, esterification, dehydrochlorination, oxidation, etc during the biodegradation of different pesticides having varying functional groups. Moreover, the biodegradation of different pesticides was found to be mediated by involvement of different enzymes including laccase, hydrolase, peroxidase, esterase, dehydrogenase, manganese peroxidase, lignin peroxidase, etc. The recent advances in understanding the fungal biodegradation of pesticides focusing on the processes, pathways, genes/enzymes and factors affecting the biodegradation have also been presented in this review article.

Biosurfactants have been considered as promising candidates for oil spill cleanup as they are generally more biodegradable, less toxic, and better in enhancing biodegradation than chemical surfactants. This study targeted the marine microbial biosurfactants to examine their enhanced production methods and application for the removal of crude oil from soil. The biosurfactants generated by Bacillus subtilis, which was isolated from the Atlantic Ocean, were investigated in this study. The economic production medium using different carbon (n-hexadecane, diesel oil, glycerol, glucose, starch, and sucrose) and nitrogen sources (NaNO₃, (NH₄)₂SO₄, and yeast extract) was studied. The best performance of biosurfactant production was achieved when using glycerol as carbon source and sodium nitrate and yeast extract as nitrogen sources in the substrate. The production rate was enhanced five times compared with that of the original screening recipe. The fermentative production of the generated biosurfactants could reduce the surface tension of water to 27 mN/m and with strong surface activity (∼36.4 mN/m) even after dilution for 10 times. The critical micellar concentration (CMC) of the product was 507 mg/L. A thin layer chromatography (TLC) analysis indicated that the purified product was a mixture of lipopeptide and glycolipid. The microbially produced biosurfactants were further examined as a soil-washing agent to enhance crude oil removal in a soil column system. The removal rates of 58 and 65 % were achieved using the biosurfactant solution with concentrations of 4 and 8 g/L, respectively. The results demonstrated the potential of marine microbial biosurfactants in cleaning crude oil-contaminated soil.