Natural products have been used to protect the skin from harmful UV radiation for decades. Due to the ecotoxicological implications of synthetic sunscreen exposure in aquatic ecosystems, there is a greater need to explore alternative sources of UV filters. Recent research has focused on discovering novel UV absorbing photoprotective molecules from nature. In response to the excessive damage caused by UVB rays, plants induce the production of high concentrations of phytoprotective secondary metabolites and anti-oxidative enzymes. Despite promising UV absorbing and photoprotective properties, plant secondary metabolites have been underutilized in topical delivery due to low solubility and high instability. Numerous phytochemicals have been effectively nanosized, incorporated in formulations, and studied for their sustained effects in photoprotection. The present review outlines recent developments in nanosizing and delivering photoprotective crude plant extract and phytochemicals from a phytochemical perspective. We searched for articles using keywords: “UV damage,” “skin photoprotection,” “photodamage,” and “nano delivery” in varied combinations. We identified and reviewed literature from 43 original research articles exploring nanosized phytochemicals and crude plant extracts with photoprotective activity. Nanosized phytochemicals retained higher amounts of bioactive compounds in the skin and acted as depots for their sustained release. Novel approaches in nanosizing considerably improved the photostability, efficacy, and water resistance of plant secondary metabolites. We further discuss the need for broad-spectrum sunscreen products, potential challenges, and future growth in this area.

As a tool for mitigating water scarcity, membrane technologies have attracted much attention in the field of industrial effluent treatment. Notably, standard membranes suffer rejection issues that lead to short membrane life and high operational costs. Thus, better rejection-resistant materials (e.g., polyethersulfone (PES) membrane blended with carboxylated multi-walled carbon nanotubes (carboxylated-MWCNT)) have been developed via a phase-inversion process. Fabricated nanocomposite membranes are characterized in terms of physico-chemical characteristics and permeation properties. The removal performance of nanocomposite membranes is evaluated via the filtration of 1000 mg/L electroneutral bromothymol blue and anionic methyl orange dyes. According to the results, the optimum blending of 0.2 wt% carboxylated-MWCNTs exhibits an increase in surface properties and thermo-mechanical properties. Moreover, carboxylated-MWCNT/PES nanocomposites exhibit the highest pure-water permeability at 20.0 L/m².h.bar and superior removal of dyes (greater than 95%) with different charges at an operating pressure of 3 bar. The carboxylated-MWCNTs/PES are promising nanocomposite membranes that exhibit favorable removal performance when dealing with industrial effluent.

Water pollution is one of the most important environmental challenges and also one of the main causes of death in the world. Transporting oil products on roads by trucks and their accidents lead to the release of these chemicals into the environment, resulting in water resources pollution. Thus, the main goal of this study is to evaluate the risk assessment of the water resources pollution in the road of Sanandaj to Marivan, Kurdistan province, Iran. Six scenarios for four types of hazardous materials in two seasons of the years were considered. The road was then segmented, and the probability of accidents in each segment was calculated by the Poisson regression method. Two scenarios were selected for analysis since truck accidents had happened mainly in spring (scenario 1) and winter (scenario 4). According to the results, the total risk of water contamination path is 20%very low, 19% low, 29% moderate, 28% high, and 4% very high. Also, according to scenario 1, 14% of the total area of the study area is very low risk, 23% low risk, 15% medium risk, 6% high risk, and 42% are very high risk. Based on scenario 4, 39% of the total area of the study area has a very low risk, 44% low risk, 13% medium risk, 4% high risk. This simply means that this road is not very suitable for transporting hazardous oil products.

The desorption of radioactive cesium (Cs) in soil is influenced by the clay mineral type, adsorption site, and concentration of Cs. In this study, experiments to detect desorption of non-radioactive and radioactive Cs from illite using oxalic acid were performed for 2 days at 70 °C in hydrothermal conditions. The results showed that the ¹³³Cs removal efficiency by oxalic acid and inorganic acid treatment was similar at high concentration (22.86 mmol/kg) of non-radioactive ¹³³Cs. In the radioactive ¹³⁷Cs experiment, the removal efficiency by oxalic acid was higher than that by inorganic acid at low concentration (0.79 × 10⁻⁶ mmol/kg) of radioactive ¹³⁷Cs. Based on the illite hypothetical frayed edge site (FES) concentration of 0.612 mmol/kg, the results suggested that ¹³⁷Cs was preferentially adsorbed to FES on illite. The ¹³⁷Cs at low concentration was difficult to remove because it was irreversible adsorption to FES, while the non-radioactive Cs at high concentration was mainly adsorbed to planar sites, and so was easy to desorb by ion exchange. Based on the results of NMR, FTIR, and XPS analyses, we concluded that the higher efficiency of ¹³⁷Cs removal at low concentration by oxalic acid treatment than by treatment with inorganic acid was because of chelation effects associated with the complexation of oxalic acid (ligands) and metal ions in irreversible site (FES).

Arsenic-polluted soil from a mining area in China was treated by electrokinetics coupled with permeable reaction barrier (EK/PRB). Batch tests with PRB media of zero valent iron (ZVI) under electric potential of 2 V cm⁻¹ for 120 h were conducted. Species and distribution of arsenic in soil after remediation were investigated to evaluate the removal mechanisms of arsenic. Results showed that ZVI-PRB was the dominant role in the removal of arsenic in the EK/PRB systems. Arsenic transferring toward the anode was greater than cathode, due to the negatively charged arsenic anions which moved to the anode chamber by electromigration. Pentavalent arsenic (As(V)) in soil could not be reduced to more poisonous trivalent arsenic (As(III)), no matter if it were treated by EK alone or EK/ZVI-PRB. The surface characterization of ZVI, which was carried out using X-ray photoelectron spectrometry (XPS), showed that the ratio of As(V)/As(III) on the surface of PRB media was lower than that in the initial soil; no As(0) was detected on the surface of used ZVI, which indicates that arsenic was removed by surface adsorption/precipitation on ZVI-PRB, accompanied by As(V) partially reduced to As(III). The results reported in this study will be beneficial to optimizing the design of batch EK/PRB system and to enlarging the field-scale system.

Globally, heavy metal (HM) pollution of soil is a serious problem that can lead to long-term toxic effects on soil. In this milieu, the present study investigated the eco-toxicological effects of three trace elements, e.g., cadmium (Cd), copper (Cu), and lead (Pb), on enzyme activities and microbial function and structural diversity in phaeozem and red soil samples. Hormesis effects of Cd, Cu, and Pb on catalase and invertase activities were observed in phaeozem soil, while for red soil, there was an inhibitory effect on the activities of catalase and invertase under Cu- and Pb-contaminated soils. The utilization of carbon sources was inhibited in Cd- and Pb-treated phaeozem soil, but higher utilization of polymers and amines exhibited in Cu-contaminated soil. Although the substrates under the contamination of Cd, Cu, and Pb had high average well color development values across incubation time, the utilization of various substrates did not exhibit a regular trend under different treatments with HMs. The denaturing gradient gel electrophoresis (DGGE) analysis showed that the HMs led to marginal changes in the number and species of soil microbes, while the similarity indices decreased in HM-treated samples, varying from 66.2 to 77.3% in phaeozem soil and from 62.8 to 66.7% in red soil. However, the sequence analysis showed that there existed metal-resistant microbial communities such as Bacillales, Bacillus, and Massilia and so on under the stress of HMs.

Disadvantages associated with chemical coagulants and goal of sustainable development have shifted the focus to natural plant-based coagulants. Raw and defatted soybean (Glycine max L.) seed powder, as innovative and eco-friendly coagulant, was appraised in detail for turbid water treatment and compared with alum in this study. Design of experiments was conducted by employing response surface method which lacks in past studies pertaining to plant-based coagulants. Experiments were conducted with lab prepared turbid water with initial turbidity of 200 NTU and wide range of pH (2–10) and dose (20–100 mg/L). Results revealed that raw and defatted soybean gave residual turbidities of 4 and 3 NTU at optimum conditions which were comparable to alum. Analysis of variance (ANOVA) identified that pH was more significant parameter as compared with dose for soybean and alum, while interaction of pH and dose was most significant in case of defatted soybean. Characterization of the coagulants and flocs, by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM), revealed that postulated mechanism of coagulation for plant-based coagulants is adsorption and charge neutralization. Cost of treating 1000 m³ of water by raw and defatted soybean is lower (US$12 and US$3.9 respectively) compared with alum (US$31.2).

This study aimed to define the optimum weight ratio between Berea Red sand (BRS)/zero-valent iron (ZVI) combinations to be used in the treatment of nitrate contaminated water. The effect of competing ions (phosphate and sulfate) on the nitrate removal efficiency of the best performing BRS-ZVI w/w ratio was also assessed. To achieve this objective, batch tests were performed under anoxic and acidic conditions (pHi = 4.5), using two combinations: 50%BRS-50%ZVI (w/w) and 25%BRS-75%ZVI (w/w), as well as 100%ZVI as a control. BRS and ZVI had 1 to 2-mm grain size. pH and nitrogen species were tested during these batch tests. Kinetic analysis was also carried out. While the removal efficiencies of 100%ZVI and 25%BRS-75%ZVI (w/w) were 70.2% and 83.1%, respectively, the experimental results showed that the combination of 50%BRS-50%ZVI (w/w) had the highest nitrate removal efficiency (99.5%), implying a synergistic effect between BRS and ZVI. Likewise, the kinetic analysis showed that the nitrate removal rate (k) increased as the BRS mass in the BRS-ZVI combination increased. Furthermore, the presence of phosphate and sulfate negatively affected the nitrate removal performance of the 50%BRS-50%ZVI combination, which was the best performing weight ratio. However, this weight ratio still showed high nitrate removal capacities in the presence of phosphate and sulfate, respectively. The 50%BRS-50%ZVI combination demonstrated to be the optimum among the used ones. However, further investigation in a large-scale reactor on this combination is recommended for further optimization of its performance.

Although numerous linear regressions have been conducted to identify driving forces of farmland investment, this study uses panel threshold techniques to explore the nonlinear effects of resource endowment, labor cost, and other potential influencing factors on China’s investment in farmland in 40 foreign countries during the period 2008–2016. Results show that increased resource endowment promotes China’s investment in overseas farmland, but the correlation gradually weakens in magnitude as levels increase. A lower labor cost attracts greater Chinese investment in farmland, but the degree of influence declines with the continued increase in labor cost. Further, host country corruption, infrastructure level, and urbanization ratio have significant negative impacts on investment, whereas an increase in China’s overall economic power significantly increases overseas farmland investment. Policy implications are proposed with respect to implementing environmental responsibility in host countries, creating comprehensive risk assessments, and optimizing the structure of overseas investment portfolios.

Biogas production from organic fraction of municipal solid waste (OFMSW) not only helps in solid waste management but also combat the food vs fuel dilemma. The presence of lignocellulosic material and other complex compounds in OFMSW hinder biogas production. Therefore, pretreatment is an essential step to increase the hydrolysis rate by converting complex compounds to simpler ones. This work was aimed at effective pretreatment of OFMSW by biological and thermo-chemical means. For biological pretreatment lignin degrading fungal strains, Phanerochaete chrysosporium and Pleurotus ostreatus were employed. Thermo-chemical treatment resulted in higher solubilisation yield in terms of sCOD and VFA making it a more effective method as compared with biological pretreatment. The optimisation of thermo-chemical pretreatment was done by the Box-Behnken design of response surface methodology (RSM). The interactive effect of influencing factors NaOH dose, temperature and time were studied on the response of sCOD, VFA and phenolic content. The sCOD and VFA values were significantly increased by increasing the NaOH concentration, temperature and time to a certain limit. The optimised condition from RSM for maximum solubilisation yield in terms of sCOD, VFA and phenolic content was found to be NaOH dose of 4.72 g/L, temperature 180 °C and time 30.3 min. Biogas production was increased by 169.5% after pretreatment at RSM optimised conditions as compared with untreated OFMSW.