The deposition of NH₄HSO₄ on catalysts is one of the key issues for selective catalytic reduction of NOₓ. In this study, NH₄HSO₄ was preloaded on catalysts, and the effects of MoO₃ and CeO₂ doping on the decomposition and reactivity of NH₄HSO₄ on V₂O₅/TiO₂ catalysts are studied. The results show that the introduction of MoO₃ and CeO₂ significantly promoted NOₓ conversion on the V₂O₅/TiO₂ catalysts. Doping with MoO₃ could effectively enhance the S and H₂O resistance of the catalysts. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis indicate that it is the strong chemical interactions between NH₄HSO₄ and the catalysts that are adverse to the decomposition of NH₄HSO₄. However, doping with MoO₃ apparently inhibits these interactions, which significantly decrease the decomposition temperature of NH₄HSO₄. In situ FTIR experiments show that the NH₄⁺ in preloaded NH₄HSO₄ could react with gaseous NO on catalysts, and doping with MoO₃ could facilitate the reaction rate.

The presence of drugs in the environment is an emerging issue in the scientific community. It has been shown that these substances are active chemicals that consequently affect aquatic organisms and, finally, humans as end users. To evaluate the toxicity of these compounds and how they affect the environment, it is important to perform systematic ecotoxicological and physicochemical studies. The best way to address this problem is to conduct studies on different aquatic trophic levels. In this work, an ecotoxicological study of six drugs (anhydrous caffeine, diphenhydramine hydrochloride, gentamicin sulphate, lidocaine hydrochloride, tobramycin sulphate and enalapril maleate) that used three aquatic biological models (Raphidocelis subcapitata, Aliivibrio fischeri and Daphnia magna) was performed. Additionally, the concentration of chlorophyll in the algae R. subcapitata was measured. Furthermore, EC50 values were analysed using the Passino and Smith classification (PSC) method, which categorized the compounds as toxic or relatively toxic. All of the studied drugs showed clear concentration-dependent toxic effects. The toxicity of the chemicals depended on the biological model studied, with Raphidocelis subcapitata being the most sensitive species and Aliivibrio fischeri being the least sensitive. The results indicate that the most toxic compound, for all the studied biological models, was diphenhydramine hydrochloride. Graphical abstract

The process of tourism economic development is accompanied by the consumption of energy and environment. It is of a big significance to measure the level of tourism economic development and regional eco-efficiency correctly to clarify the relationship between them, as it contributes to realizing the high-quality development of the tourism economy and the construction of “beautiful China”. On the basis of the panel data of China’s 30 provinces and cities from 2002 to 2016, the paper intends to evaluate the regional eco-efficiency and tourism economic development level by using the super-efficiency DEA model and the grey entropy weight method, and then construct spatial panel econometric model which is based on the previous data to deeply discuss the influence of tourism economy development on regional ecological efficiency and its spatial effect. The research shows that (1) regional ecological efficiency has significant spatial dependence and spatial aggregation characteristics. With the passing of time, this kind of positive spatial autocorrelation is gradually strengthened. (2) In the long-term development, tourism economic development and regional ecological efficiency show a more obvious “Kuznets curve” effect. (3) The “U”-curve relationship between urbanization, environmental regulation, and regional eco-efficiency was confirmed. (4) In the process of tourism economic transformation and development, industrial pollution control, environmental regulation, technological level, urbanization, and investment openness are the main factors that affect the improvement of ecological efficiency in the local region. (5) Tourism economic development and urbanization levels have different spatial spillover effects in different periods, while investment openness has obvious positive spillover effects.

This work was dedicated to the elaboration of new composite materials based on activated carbon and titanium oxide as an ecological solution for the cleaning of water contaminated with pharmaceutical pollutants. Such new composite materials allowed the combining of adsorption and photocatalytic process, which allows a cleaning process that is low cost making them promising materials. The functionalization of the surface of activated carbon (AC) by TiO₂ nanoparticles forms the core of the nanocomposite material. This was accomplished using sol-gel process with molar ratios Rₙ (nTᵢ/nAC) in the range of 1/10 to 7/10 followed by a calcination step (400 °C, N₂, 2 h). Using various characterization techniques, AC surface functionalization was confirmed and the formation of a TiO₂ coating on the AC was noticed with TiO₂ under its unique anatase crystallographic form. The study of adsorption and photocatalytic degradation of the sulfamethazine antibiotic demonstrated that the most photoactive nanocomposite corresponds to the one with Rₙ = 0.5. Freundlich model was proved to be a perfect fit with the experimental results stating that the adsorption is of multilayer nature on the surface of the adsorbent and with interactions between the pollutants adsorbed on its surface. The photocatalytic degradation of the remaining pharmaceutical pollutant in the solution was evidenced and essentially occurred through the involvement of hydroxyl radicals formed by the excitation of the photocatalyst. The formation of the photoproducts analyzed by the LC/MS technique implies the splitting of the sulfonamide bridge, and by the hydroxylation of the aromatic ring and the pyrimidine group.

A novel biomaterial was prepared by the immobilization of Phlebia gigantea cells in the medium containing lignocellulosic waste and used for the first time in the bioremediation purpose. The developed new biocomposite possesses higher Pb(II) retention potential when compared with the free microbial cells. It could remove Pb(II) up to 74.11% at a biosorbent dosage of 4.0 g L⁻¹. Surface characterization was carried out through zeta potential, EDX, SEM, and IR studies to understand the metal-biocomposite interactions. The biosorption amount at equilibrium slightly decreased with the increase of the solution temperature. Kinetic data indicated Pb(II) biosorption onto suggested biocomposite fits well with the pseudo-first-order model. Biosorption equilibrium data suited Langmuir model with the highest coefficient of determination values. The immobilized material reached to maximum monolayer Pb(II) retention capacity (1.449 × 10⁻⁴ mol g⁻¹) within the short equilibrium time (10 min). The designed biocomposite was also adapted to continuous flow mode sorption process. Regeneration tests by dynamic flow mode confirmed reutilization potential of biocomposite.

There have been many studies on the model of volatile organic compound (VOC) emissions from individual dry building material and have been validated in the chamber. Actually, VOC emitted from multiple dry building materials simultaneously indoor. The concentration of VOC indoor increases and will inhibit the VOC emission of dry building materials indoor. This paper developed a new model predicting indoor VOC concentrations caused by simultaneous emissions from multiple dry building materials, with a consideration of impact from dynamic VOC concentrations on the emission rate. The model has been used to predict the VOC emissions from a combination of medium-density fiberboard (MDF) and consolidated compound floor (CCF) simultaneously. The study demonstrated a good prediction performance of the newly proposed model, against field experimental data. The study also showed that when multiple dry building materials emit pollutants in a common space, a mutual inhibition effect could be observed. Furthermore, when multiple dry building materials emit VOC simultaneously, the change of VOC concentrations in the air followed the trends of VOC emissions from building materials with higher initial concentration (C₀), diffusion coefficient (Dₘ), and the partition coefficient (Kₘₐ).

A study was carried out to assess the levels and effects of atrazine, dimethoate, and dichlorodiphenyltrichloroethane on freshwater fish (Oreochromis mossambicus). Water and fish were sampled once from a dam within the Hippo Valley A2 farmlands in Chiredzi, in the southeastern part of Zimbabwe. The samples were screened for atrazine, dimethoate, and dichlorodiphenyltrichloroethane (DDT), the pesticides commonly used in the region. Atrazine and dimethoate are pesticides commonly used in the control of weeds and pests in the agricultural production of sugarcane in Hippo Valley, Chiredzi region. The effects of the pesticides on biochemical endpoints of the sampled fish were determined. The analyzed biochemical end parameters were superoxide dismutase, catalase, glutathione S-transferase, and glutathione peroxidase activities in liver and white muscle fish extracts. Dichlorodiphenyltrichloroethane was observed in water and fish muscle tissue at concentrations of 131.3 μg/l and 171.7 μg/kg, respectively, while atrazine was detected at concentrations of 6.15 μg/l and 142.0 μg/kg in water and fish muscle tissue, respectively. The observed concentrations of atrazine and DDT in water samples were above the limits permissible by the World Health Organization in drinking water. Dimethoate was found in concentrations of 4.21 μg/l and 1.30 μg/kg in water and fish muscle tissue respectively. The observed concentration of dimethoate in water was below the acceptable limit set by the Guidelines for Canadian Drinking Water. Antioxidant enzyme activities were increased significantly (p < 0.05) in fish exposed to water from Hippo Valley, Chiredzi, when compared with the controls. The enhanced activities of the studied antioxidant enzyme system were attributed to exposure to pollutants in the water body. Alterations of the biochemical integrity of fish indicate negative effects of the pesticides on the well-being of fish and undoubtedly other aquatic biota as well.

Biosynthesized nanoparticles proposed to have antiplasmodial activities have attracted increasing attention for malaria that considered being one of the foremost hazardous diseases. In this study, Indigofera oblongifolia leaf extracts were used for the synthesis of silver nanoparticles (AgNPs), which were characterized utilizing transmission electron microscopy. We investigated the antiplasmodial and hepatoprotective effects of AgNPs against Plasmodium chabaudi–induced infection in mice. Treatment of the infected mice with 50 mg/kg AgNPs for seven days caused a significant decrease in parasitemia and reduced the histopatholoical changes in the liver, as indicated by Ishak’s histology index. Further, the AgNPs alleviated the oxidative damage in the liver infected with P. chabaudi. This was evidenced by the changed levels of malondialdehyde, nitric oxide, and glutathione, as well as increased catalase activity after treatment with AgNPs. In addition, levels of the liver enzymes alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase were increased after treatment. Moreover, the findings showed the efficiency of AgNPs in improving the infected mice’s erythrocyte counts and hemoglobin content. Generally, our results reported that AgNPs possess antiplasmodial and hepatoprotective properties.

The objective of this research project was the design and development of an integrated model for odor emission estimation in wastewater treatment plants. The SMAT’s plant, the largest wastewater treatment facility in Italy, was used as a case study. This article reports the results of the characterization phase that led to the definition and design of the proposed conceptual model for odor emission estimation. In this phase, concentrations of odor chemical tracers (VOC, H₂S, NH₃) and odor concentrations were monitored repeatedly. VOC screening with GC-MS analysis was also performed. VOC concentrations showed significant variability in space and magnitude. NH₃ and H₂S were also detected at considerable concentrations. Results were elaborated to define a spatially variable linear relationship between the sum of odor activity values (SOAV) and odor concentrations. Based on the results, a conceptual operational model was presented and discussed. The proposed system is composed by a network of continuous measurement stations, a set of algorithms for data elaboration and synchronization, and emission dispersion modeling with the application of Lagrangian atmospheric models.

Biotic interactions shape the community structure and function of ecosystems and thus play an important role in ecosystem management and restoration. To investigate how water temperature (related to the season) and water depth (related to spatial patterns of river morphology) affect macrophyte–bacterioplankton interactions in a groundwater-fed river, we conducted the structural equation modeling on datasets grouped by hydrological conditions. In addition to direct effects on macrophyte growth and/or bacterioplankton development, water temperature and water depth could both regulate the role of different nutrients (inorganic and organic) on affecting these biological indicators. Deeper water depth intensified the positive relationship between macrophytes and bacterioplankton, while higher temperature switched the relationship from being positive to negative. Our study provides empirical evidences that abiotic variables, even with relatively low fluctuations, play a critical role in regulating the patterns and strengths of interaction between macrophytes and bacterioplankton.