Sodium silicate is always used as an activator for the synthesis of geopolymer. However, the effect of sodium silicate concentration on the geopolymer used as adsorbent was still unclear. Therefore, the immobilization of Sr²⁺ in geopolymers activated by different concentrations of sodium silicate was studied through kinetic and isotherm modeling and solid characterizations including XRD, FTIR, TG, SEM–EDS, and N₂ adsorption–desorption isotherm. The adsorption amount of Sr²⁺ decreased with the sequence of S1, S2, and S3. According to the kinetic and isotherm modeling results, these sorption processes fitted better with pseudo-second-order, mainly governed by film diffusion. However, the diffusion mode was gradually closed to particle diffusion as for the sequence of S3, S2, and S1. Besides, the Langmuir model can be more befitting to sorption data than the Freundlich model, and the free energies decreased with the order of S1, S2, and S3. In addition, the specific surface areas did not change regularly with S1, S2, and S3. Thus, the distribution of Al tetrahedrons has a decisive role in the sorption process of Sr²⁺, even though the specific surface area is also a critical factor. More Al tetrahedrons can be formed under the activation of sodium silicate with higher concentration, leading to the low Si/Al molar ratio of the as-synthesized geopolymer.

The rupture of Fundão dam was the biggest environmental disaster of the worlds’ mining industry, dumping tons of iron ore tailings into the environment. Studies have shown that the Fundão dam’s tailings are poor in nutrients and have high Fe and Mn concentration. In this context, our objective was to evaluate the growth performance of two native tree species (Bowdichia virgilioides and Dictyoloma vandellianum) in two treatments: fertilized soil and fertilized tailings. We hypothesize that the high concentrations of iron and manganese in the tailings can impair the growth performance of plants by interfering with the absorption of nutrients made available through fertilization. Soil and tailings samples were collected in the municipality of Barra Longa (MG, Brazil), and then fertilized with mixed mineral fertilizer (“Osmocote Plus 15–9-12” at 7.5 g L⁻¹). The experiment was conducted for 75 days in a greenhouse using 180 cm³ tubes. We evaluate chlorophyll content, maximal PSII quantum yield, root length, shoot length, root:shoot ratio, leaf area, specific leaf area and leaf area ratio, dry mass, macro- and micronutrients concentration in the tissues, and metal translocation factor. Although assuring the adequate levels of the main nutrients to plant growth (N, P, K, Ca, and Mg), the fertilization did not reverse the negative effect of tailing on these species. The high concentration of Fe in the tissues associated with less biomass production, lower plant height, smaller leaf area, bigger specific leaf area, and reduced chlorophyll content indicates a probable phytotoxic effect of iron present in the tailings for D. vandellianum. Our results base further field evaluations and longer experiments, which will facilitate the understanding of the performance of tree species submitted to tailings with fertilization. So far, this study suggests that B. virgilioides are more tolerant to excess Fe from the tailings of Fundão dam than D. vandellianum.

Since the advent of photocatalytic degradation technology, it has brought new vitality to the environmental governance and the response to the energy crisis. Photocatalysts harvest optical energy to drive chemical reactions, which means people can use solar energy to complete some resource-consuming activities by photocatalysts, such as environmental governance. In recent years, researchers have tried to combine photocatalyst TiO₂ with building materials to purify urban air and obtained good results. One of the important functions of photocatalysts is to degrade organic pollutants in water through light energy, but this technology has not been reported in the practical application areas. To extend this technology to practical application areas, photocatalytic concrete for degrading pollutants in waters was proposed and demonstrated for the first time in this paper. The photocatalytic concrete proposed based on the K-g-C₃N₄ shows a strong ability to degrade the organic dyes. According to the experiment results, the angle of light source plays an important role in the process of photocatalytic degradation, while waters with pH value of 6.5–8.5 hardly influenced the degradation of organic dyes. When the angle of light source is advantageous for photocatalytic concrete to absorb more visible light, more organic dyes will be degraded by photocatalytic concrete. The degradation rate of methylene blue could reach about 80% in ½ hour under desirable conditions and is satisfied compared with that of reported works. This study implicates that photocatalytic concrete can effectively degrade organic dyes in water. The influences of changes in the water environment hardly affect the degradation of organic pollutants, which means photocatalytic concrete can be widely used in green infrastructures to achieve urban sewage treatment.

Climate change influences the current tropospheric ozone (O₃) budget due to industrialization and urbanization processes. In recent years, the impact of elevated O₃ on crop development and yield loss has emerged as one of the most important environmental issues, particularly in rural and suburban areas of the lower Indo-Gangetic Plains of India. The impact of the current tropospheric ozone (O₃) on the crop yield, photosynthetic yield, and enzymatic antioxidants of six rice (Oryza sativa L.) cultivars (IR 36, MTU 1010, GB 3, Khitish, IET 4786, and Ganga Kaveri) was investigated with and without the application of ethylenediurea (EDU). The results revealed that O₃ stress significantly affected crop yield, photosynthetic yield, and antioxidant enzymes. The findings showed that O₃ toxicity induces oxidative stress biomarkers, i.e., malondialdehyde (MDA) content, and was manifested by increasing the enzymatic antioxidants, i.e., superoxidase dismutase (SOD) and catalase (CAT) in four rice cultivars (IR 36, GB 3, IET 4786, and Ganga Kaveri). At the same time, the results also illustrated that the rice cultivars MTU 1010 and Khitish are more tolerant to O₃ stress as they had less oxidative damage, greater photosynthetic SPAD value, SOD and CAT activities, and lower MDA activity. The results also elucidated that the application of EDU decreased O₃ toxicity in sensitive cultivars of rice by increasing antioxidant defense systems. The current O₃ level is likely to show an additional increase in the near future, and the use of tolerant genotypes of rice may reduce the negative impacts of O₃ on rice production.

Studies about the pneumonia morbidity effects of various air pollution exposure are still limited in China. We aimed to explore the short-term effect of air pollutants exposure on pneumonia admission and identify the vulnerable groups in Qingdao, China. From January 2015 to October 2017, a prospective cohort involving 433,032 participants across 3 counties in Qingdao were enrolled in the study. Distributed lag nonlinear model (DLNM) was applied to assess the associations between air pollutants and pneumonia hospitalizations. There were 636 cases of pneumonia, with an annual incidence density of 54.33 per 100,000 person-years (95% CI: 50.11, 58.56). A 10 μg/m³ increment of sulfur dioxide (SO₂) distributed at a 4-week lag in Qingdao was associated with increased pneumonia hospitalizations, with a risk ratio of 2.10 (95% CI: 1.06, 4.13). Subgroup analyses indicate that PM ≤ 2.5 μm in aerodynamic diameter and SO₂ showed stronger effects on pneumonia in females than males, whereas people in urban regions were more vulnerable to nitrogen dioxide and ozone (O₃) than the others. We also observed distinct acute effects and harvesting effects of SO₂ and O₃ on pneumonia in urban areas. Strategies should be taken to further reduce levels of ambient PM₂.₅, SO₂, and O₃.

This research work describes the degradation of quinoline yellow (QY) in aqueous solutions by the heterogeneous Fenton and photo-Fenton processes in the presence of CuO/Fe₂O₃ photocatalyst. CuO/Fe₂O₃ derived from LDH structure was synthesized by the co-precipitation method. The physiochemical characteristics of CuO/Fe₂O₃ were described by XRD, TEM/SEM, BET surface area, and FTIR techniques. The effects of pH, H₂O₂ concentration, dye concentration, catalyst dose, reaction temperature, and reusability of catalyst on the QY decolorization efficiency were studied. The results indicated that a complete removal of QY was achieved within 150 min, when the H₂O₂ and QY concentrations were 27.6 mM and 100 mg/L, respectively. The rate constants for QY removal by the heterogeneous Fenton system were calculated, and the experimental data were found to fit the pseudo-first order model. Under optimal conditions, the rate constants were, respectively, 0.02032 and 0.01715 min⁻¹ for the photo-Fenton and Fenton systems; this means that the addition of light has not a noticeable effect.

In the 14th Five-Year Plan, China clearly proposed to achieve carbon peak by 2030 and carbon neutralization by 2060, which will be incorporated into the Ecological Civilization Construction. Therefore, it is particularly important to control the consumption of fossil energy in rural areas. Under this background, the paper is based on the filed survey data of rural households and uses the method of CLAD (the censored least absolute deviations) estimation of Tobit model to study the influencing factors and structural characteristics of rural households’ energy consumption. The results show that the consumption of traditional energy with low-quality takes a main proportion of total energy consumption in rural households, which is unreasonable and needs transforming urgently. Also, there is heterogeneity among regions. Family characteristics, family wealth, and energy conservation initiative have an impact on total energy consumption and different types of energy. Especially, households with high frequency of energy conservation behavior and strong policy perception will reduce the consumption of high-polluting firewood and increase the use of coal and electricity.

Groundwater quality assessment is crucial to the sustainable utilization of global groundwater resources. This study examined the current groundwater quality circumstance and the associated health risks from nitrate contamination for different age groups in the Heilongdong Spring Basin, a typical headwater basin of the North China Plain. A total of 39 groundwater samples were collected, and major ions were measured during the two field investigations (December 2017, August 2018). Results showed that most of groundwater chemical parameters were below the World Health Organization standards with a few exceptions. Anthropogenic sources and aquifer heterogeneity were jointly responsible for nitrate pollution in more than half of water samples. For drinking purpose, the groundwater was excellent or good in the western and southeastern regions where groundwater recharge and discharge mainly occur. However, the poor water quality samples were observed in the central and northern parts of the study area, which may be attributed to the slow or stagnant flow in the transitional zone. Additionally, the farmland irrigated with such groundwater will not be exposed to sodium or magnesium hazard but will suffer from the potential salinity hazard. The health risk for different age groups in the study area varied significantly, generally in the order of infants > children > adult females > adult males. The findings of this work provide valuable information for decision-makers to formulate sustainable strategies for groundwater resources development in these headwater basins of the North China Plain.

The RhoA gene showed an important genotypic association with nicotine dependence and smoking initiation. The current study aims to investigate the effect of the Rho GTPase inhibitor ML141 in the progression of nicotine dependence in a mice model of precipitated nicotine withdrawal syndrome by mecamylamine.The experimental procedure involved administration of 2.5 mg/kg nicotine dissolved in normal saline subcutaneously (s.c) four times a day consecutively for 7 days and last single dose in the morning on 8ᵗʰ day. ML-141 was dissolved in dimethyl sulfoxide (DMSO) and was administered daily with nicotine as corrective treatment at a dose of 1,5 and 10 mg/kg (p < 0.05). An injection of 3 mg/kg of mecamylamine intraperitoneal (ip) was given an hour later than the last nicotine dose on the day 8 to precipitate withdrawal of nicotine and withdrawal severity was assessed by measuring hyperalgesia, piloerection, jumping frequency, tremors, and withdrawal severity score (WSS). Various behavioural changes such as hyperalgesia, piloerection, jumping frequency, and tremors were monitored and WSS was calculated. ML-141 a selective Rho GTPase inhibitor was found to show dose-dependent effect on all these parameters. Inhibition of Rho GTPase was found to reduce the severity of withdrawal syndrome; therefore, it can be concluded that Rho GTPase would serve as a suitable biological target by regulating the reward system in brain and could be used as new target for drug discovery.

This research reports the use of biodegradable and flexible composites for the removal of the 2,6-dichlorobenzamide (BAM) pesticide from drinking water. Rice paper (a biodegradable substrate) and Ag/BaMoO₄ (MOBA) nanoparticles were employed to fabricate these composites. The SEM images showed that the MOBA nanoparticles with sizes of 300–800 nm decorated the surface of the biodegradable substrate and formed porous agglomerates, which have sizes of 1–3 μm. The MOBA powders were dispersed in drinking water polluted with BAM and were exposed to 4 h of UV-VIS irradiation, producing a maximum degradation of 82% for the BAM. Moreover, the flexible and biodegradable rice/MOBA composite produced a maximum removal percentage of 95% for the BAM. Also, we studied the effect of pH of the initial solution utilizing both powders and composites. From here, we found that a pH of 10 leads to a complete degradation of BAM after 4h, while a pH of 3 degraded only 37–47% of BAM for the same reaction time. According to the scavenger experiments, the •OH radical and the h⁺ were the main oxidizing agents for the BAM. Overall, the biodegradable photocatalytic composites are a reliable and a low-cost alternative to eliminate pesticides from the drinking water and can find application in water purification processes.