The extreme persistence, bioaccumulative, and toxicity tendencies of per- and polyfluoroalkyl substances (PFAS) have contributed to the ever-increasing quest for effective and low-cost technologies for removing PFAS from aqueous solutions. Therefore, in the present study, maize tassel (MT) was activated using phosphoric acid. The chemically activated maize tassel (CAMT) was thereafter applied as an adsorbent for removing perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) from aqueous media in comparison with the inactivated MT. The adsorption behaviors of PFOS and PFOA onto MT and CAMT were investigated via adsorption experiments. It was found that the isothermal data fit better with the Freundlich isotherm model than with the Langmuir isotherm model. Maximum adsorption capacities of 1552.5 mg g⁻¹ (3.10 mmol g⁻¹) and 380.32 mg g⁻¹ (0.92 mmol g⁻¹) were recorded for PFOS and PFOA, respectively, using CAMT, when the Freundlich model was applied. Equilibrium was attained within 60 min using both MT and CAMT. The pseudo-second-order kinetics model suited the kinetics data better. It was observed from the thermodynamic studies that the adsorption mechanism of PFOS and PFOA on MT and CAMT is spontaneous and feasible. All the values for the Gibb’s free energy change (ΔG⁰, kJ mol⁻¹) obtained in the present study were below − 20 kJ mol⁻¹. The adsorption of PFOS and PFOA using CAMT is exothermic in nature (enthalpy, ΔH⁰ was negative) whereas the adsorption of PFOS and PFOA using MT is endothermic. The PFOS and PFOA adsorption processes using both MT and CAMT were greatly influenced by electrostatic and hydrophobic interactions. Graphical abstract

Fe-Mn/TiO₂ catalysts were prepared through the wet impregnation process to selective catalytic reduction of NO by NH₃ at low temperature, and series of experiments were conducted to investigate the effects of key precursors on their SCR performance. Ferric nitrate, ferrous sulfate, and ferrous chloride were chosen as Fe precursors while manganese nitrate, manganese acetate, and manganese chloride as Mn precursors. These precursors had been commonly used to prepare Fe-Mn/TiO₂ catalysts by numerous researchers. The results showed that there were distinct differences in NO conversion efficiencies at low temperature of catalysts prepared with different precursors. Catalysts prepared with ferric nitrate and manganese nitrate precursors exhibited the best catalytic performance at low temperature, while three kinds of catalysts prepared with manganese chloride precursors exhibited significantly low catalytic activity. All catalysts were characterized by XRD, SEM, H₂-TPR, NH₃-TPD, and XPS. The results indicated that when the catalysts were prepared with manganese nitrate or manganese acetate as precursors, Mn⁴⁺ contents and Oᵦ/(Oᵦ + Oα) ratios decreased in an order of ferric nitrate > ferrous sulfate > ferrous chloride, which was consistent with the change of catalytic activities of the corresponding catalysts at low temperature. It can be found that the excellent catalytic performance of Fe(A)-Mn(a)/TiO₂ was ascribed to high redox property and enrichment of Mn⁴⁺species and surface chemical labile oxygen groups.

The adaption of the open-up reform policies in China some three decades ago has resulted in a rapid economic transformation of which the tourism sector has equally witnessed fast development. Therefore, the essence of this article is to review the evolution and expansion of the tourism industry in China and its obligation to observing international sustainable development policies and practices. Indications of the current policy regime, establishment, and institutions, sustainable development strategies to ensure continuity and availability of resources for future use, environmental sustainability laws and regulations, and promotional events for the development of the tourism industry are made available in this article. In effect, this article reviews how the activities of the tourism sector impacts on the environment. The findings show that China in its quest to be a world leader of tourists’ destination has impacted negatively on the environment which by extension affect the economy and society at large. On the other hand, as a leading nation in the United Nations, China has in contemporary times adapted sustainable development strategies to help safeguard the environment. However, more needs to be done in the area of advanced technology and renewable energy.

The possibility of superficial foot mycoses to spread through contaminated mosque carpets between worshipers imposes a great health burden and is never addressed in Riyadh, SA. We aimed to assess the prevalence of fungal infections, especially human dermatophytosis acquired from mosque carpets, in five different regions of Riyadh, Saudi Arabia and establish a means of contamination control. A cross-sectional study of 100 mosques in Riyadh, Saudi Arabia, was conducted, using a multistage random cluster sampling technique. The study included mosques that had an ablution area and regularly hosted five prayers a day. Sterile swabs were used for sampling, and the samples were transported to the laboratory for culture and analysis using a micro-scan system. A total of 199 (65%) samples contained several fungal species. Rhodotorula (74%), Cladosporium (47%), Bipolaris (46.6%), other yeasts (43.7%), Alternaria (40%), dematiaceous molds (34%), Curvularia (32.4%), and Candida (31%) were the most frequently isolated species. Species belonging to several other genera were also detected. This study revealed a relatively high prevalence of fungal organisms in mosque carpets in Riyadh, suggesting the need for implementing new strategies and laws to increase the level of hygiene awareness among worshipers and mosque caretakers to limit the spread of foot fungal infections.

Photocatalysis has emerged as a promising approach for treating environmental pollution. In this study, TiO₂/sponge composites with good photocatalytic activity in visible light were prepared via a simple and efficient low-temperature process and applied to the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) present in papermaking wastewater. The process conditions for preparing TiO₂/sponge composites were optimized by varying the TiO₂ dosage, cellulose dosage, and surfactant concentration. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) results showed that TiO₂ successfully adhered to the sponge surface and that the composites achieved a good recycling effect. Degradation occurred under visible light, and a degradation rate of 81% for 2,4,6-TCP with initial concentration of 20 mg/L was achieved in 4 h. The fragments were analyzed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS), which revealed the formation of 2-hydroxyvaleric acid (2-HVA) as a degradation product; a possible degradation mechanism is proposed to interpret these findings. Visible-light photocatalysis shows high potential for the rapid and environmentally friendly destruction of organic pollutants in papermaking wastewater.

The concern with the environment and the depletion of natural resources has aroused the interest for the rational use and recycling of water. Therefore, this study evaluated the capacity of the Trametes sp. M3 isolate in the bioremediation of Reactive Blue (RB) 268 dye and its potential for use as an adsorbent in the treatment of textile effluents. In a solid medium containing RB 268, the discoloration rate was 1.00 and the growth rate was 1.4 cm/day. When evaluated in the in vivo biodiscoloration process, 100% of the dye lost its color after 120 h. The oxidative enzyme laccase was found in cultures containing the dye with high activity, indicating that it underwent induction. The chromatogram after cultivation of the fungus showed that there was a change in the structure of RB 268. The mycelium of the culture with the dye was analyzed by FTIR, pointing to an adsorption of RB 268 or its metabolites despite the absence of the color. In the biosorption, the best results were obtained when the mycelium was treated with HCl. The toxicity of the medium decreased after the cultivation of the fungus allowing the survival of the microcrustaceans in the acute toxicity bioassay.

Multi-element concentrations (Al, As, Cd, Cr, Hg, Ni, Pb, Se, and Sr) were analyzed in the muscle of six fish species (Hoplias malabaricus, Oligosarcus jenynsii, Rhamdia quelen, Bryconamericus iheringii, Astyanax fasciatus, and Odontesthes bonariensis) with different diets and habits from the Río Tercero Reservoir (RTR) in Córdoba, Argentina, during the wet and dry seasons. Besides, potential human health risks, associated with the consumption of these elements, have been assessed considering the average daily intake (EDI) in children and adults. Additionally, the target hazard quotient (THQ) and carcinogenic risk (CR) were evaluated taking into account the intake by the general population, fishermen, and consumption frequency recommended by the American Heart Association (AHA), the maximum scientific reference in cardiology in the USA and worldwide. All species presented quantifiable values in muscle for all the analyzed elements (Al, As, Cr, Hg, Ni, Se, and Sr), except for Cd and Pb, being Al and Sr the most accumulated elements in all species in both seasons. The consumption of edible muscles of the species studied in this reservoir represents a toxicological risk to humans. Mercury and As were the main elements that presented a health risk through the consumption of fish. Their concentrations in most fish species were above the maximum daily allowable concentrations, and THQ values were several times greater than 1. In addition, according to AHA recommendations, the cancer risk caused by As was greater than the acceptable value of 10⁻⁴ in all species studied, and in both seasons, with the exception of A. fasciatus, in the rainy season. These results indicate that the consumption of fish from the RTR exposes the inhabitants to possible health risks, especially when considering the consumption frequency recommended by the AHA. Therefore, fish intake from this reservoir should be limited to minimize potential risks to the health of consumers. Finally, the results of this study are useful for controlling pollution and developing preventive and palliative policies to protect populations in contact not only with the reservoir but also with other areas of the world with similar conditions.

Frequent heavy air pollution occurred during the winter heating season of northern China. In this study, PM₂.₅ (particles with an aerodynamic diameter less than 2.5 μm) was collected from a coastal city of China during the winter heating season from January 1 to March 31, 2018, and the soluble ions, organic carbon (OC), elemental carbon (EC), bacterial, endotoxin, and fungal concentration in PM₂.₅ were analyzed. During the winter heating season, PM₂.₅ and bioaerosols increased on polluted days, and the secondary inorganic ions, including NO₃⁻, NH₄⁺, and SO₄²⁻, increased significantly. Meteorological factors, such as wind direction and wind speed, had major impacts on the distributions of PM₂.₅ and bioaerosols. Pollutant concentration was high when there was a westerly wind with the speed of 3–6 m/s from inland area. Using the air mass backward trajectories and principal component analysis, we elucidate the potential origins of bioaerosol in PM₂.₅. The backward trajectory suggested that air mass for polluted samples (PM₂.₅ > 75 μg/m³) commonly originated from continent (9.62%), whereas air masses for clean samples (PM₂.₅ < 35 μg/m³) were mainly from marine (56.73%). The interregional transport of pollutants from continental area contributed most to PM₂.₅. Principal component analysis of the water-soluble ions and bioaerosol indicated that air pollution of the coastal city was greatly affected by coal combustion, biomass burning, and regional transmission of high-intensity pollutants from continent. Among that, interregional transport, biomass burning, and dust from soil and plants were main sources of bioaerosol. Our findings provide important insights into the origins and characteristics of bioaerosol in PM₂.₅ during the winter heating season of the coastal city in northern China.

Water is one of the receptors media more affected by the environmental impacts, especially caused by mining sulfides exploitation. Acid mine drainage (AMD) is the main problem associated with these mining operations, producing extremely high impacts, and in many cases irreversible, still remaining nowadays. Diatoms, are the taxonomic algal group most used in environmental studies, to assess the water quality of rivers. From a monitoring perspective, the diagnosis of AMD contamination through the use of diatoms has proved to be an effective ecological tool to assess the impact and select the preventive and corrective measures more adequate to treat these impacted sites. In the present work, the existing relationships between biological and physicochemical indicators of acid mine drainage processes (AMD) in all the reservoirs affected by AMD in the Iberian Pyrite Belt (IPB) were studied through the use of fuzzy logic and data mining techniques that in contrast to the classic statistical treatments. The fuzzy rules show the relationship between biological and physical-chemical indicators, demonstrating the presence of a perfect correlation in all cases; thus, the numbers of species and pH have the same behavior, and inverse to that presented by the percentage of Pinnularia and the metallic charge and sulfates. These techniques improve the work considerably and make easier the knowledge of the involved processes, allowing a better discrimination of the diatoms responses to the stimuli caused by the hydrochemical changes imposed by the processes affecting water quality.

Mining is an important activity for the economic development of many countries. However, this activity produces toxic residues that pollute water and the environment. The heavy metal removal from effluents of acid mine water is crucial to avoid environmental pollution. The microalga Nannochloropsis oculata was cultured in algal medium, with the addition of 1.16, 1.74, 2.32, 3.48, and 4.64 mg Cu²⁺ L⁻¹ coming from acid mine water to assess its removal capacity and the effect of copper content on the cell density and lipid productivity. The results showed that N. oculata removed up to 94.88 ± 0.43% at copper concentration than 1.74 mg Cu²⁺ L⁻¹; additionally, a positive effect on the lipid content was found at copper concentration to be higher, 4.64 mg Cu²⁺ L⁻¹, yielding 77.04 ± 2.60% of lipid content, twice as high as that achieved in the control culture of 33.058 ± 5.398%, thus potentiating the biodiesel production. These findings are favorable because they indicate that microalgae can remove copper added in the culture and present in acid mine water and can yield high lipid content at the same time. The cell density and growth rate decreased with increased concentrations of copper in the culture medium.