To remove the extra ammonium-nitrogen (NH₃-N) and phosphorus (P) from contaminated water, a novel granular adsorbent (GAZCA) was fabricated with zeolite powders and Al–Mn binary oxide (AMBO) via the compression method. The SEM-EDS and mapping and XRD results illustrated the microstructure of GAZCA: the homogeneous aggregation of zeolite and AMBO nanoparticles with their crystal integrity and the uniform distribution of Al/Mn/Si/O elements on the adsorbent surface. FTIR and XPS results demonstrated the existence of impregnated sodium cations and hydroxyl groups, which were responsible for the removal of NH₃-N and P, respectively. The results of BET analysis and compression tests exhibited a high surface area (14.4 m²/g) and a satisfactory mechanical strength of GAZCA. Kinetic adsorption results showed a fast adsorption rate for NH₃-N and P, and mutual inference was not observed between the adsorption kinetics of NH₃-N and P in the bi-component system. The adsorption isotherm results demonstrated that the maximum adsorption capacities of NH₃-N and P were calculated as 12.9 mg/g and 9.3 mg/g via the Langmuir model, respectively. In the bi-component system, the adsorption capacities of NH₃-N and P were maintained at low and moderate concentrations and decreased at high concentrations due to the blockage effects of NH₄MnPO₄·H₂O precipitates. The removal efficiency of NH₃-N could be maintained in a wide pH range of 4~10, while P adsorption was inhibited at alkali conditions. The solution of sodium bicarbonate (0.4 M) was used for the regeneration of saturated adsorbents, which permitted GAZCA to keep 98% and 78% of its adsorption capacity for NH₃-N and P even after three regeneration and reuse cycles. Dynamic experiments illustrated that a satisfactory performance was obtained for the in situ treatment of simulated N- and P-contaminated water by using a column reactor packed with GAZCA, thus further confirming its great potential for the control of eutrophication.

The implementation of the extended producer responsibility (EPR) for e-waste is an important measure to develop an ecological civilization. In order to advance manufacturing enterprises to effectively implement resource and environmental responsibility, this study investigates the main causes of environmental regulation failure from the perspective of government and enterprises. The game theory was used to establish an evolutionary game model between government regulatory departments and electronic and electrical products’ manufacturing enterprises. A system dynamic model was utilized to construct the stock-flow graph of the game between government and enterprises, and to carry out simulation analysis under different strategies. The results found that the probability of an enterprise undertaking extended responsibility gradually increased and stabilized with the increase of government supervision and punishment intensity; the government’s regulatory probability and punishment are important factors affecting the enterprises’ compliance with regulations and responsibilities. The study suggests that government should focus on strengthening environmental regulations from the aspects of improving laws and regulations, establishing a regular monitoring system and innovating incentive and constraint mechanism.

The purpose of this study was to investigate the aqueous phase photochemical behavior of enoxacin (ENO), an antibiotic selected as a model pollutant of emerging concern. The second-order reaction rate constants of ENO with hydroxyl radicals (HO●) and singlet oxygen (¹O₂) were determined at pH 3, 7, and 9. Also, the rate constants of the electron transfer reaction between ENO and triplet states of chromophoric dissolved organic matter (³CDOM*) are reported for the first time, based on anthraquinone-2-sulfonate (AQ2S) as CDOM proxy. The sunlight-driven direct and indirect ENO degradation in the presence of dissolved organic matter (DOM) is also discussed. The results show that direct photolysis, which occurs more rapidly at higher pH, along with the reactions with HO● and ³AQ2S*, is the key pathway involved in ENO degradation. The ENO zwitterions, prevailing at pH 7, show kENO, HO●, kENO,₁O₂, and kENO,₃AQ₂S* of (14.0 ± 0.8) × 10¹⁰, (3.9 ± 0.2) × 10⁶, and (61.5 ± 0.7) × 10⁸ L mol⁻¹ s⁻¹, respectively, whose differences at pH 3, 7, and 9 are due to ENO pH-dependent speciation and reactivity. These k values, along with the experimental ENO photolysis quantum yield, were used in mathematical simulations for predicting ENO persistence in sunlit natural waters. According to the simulations, dissolved organic matter and water depth are expected to have the highest impacts on ENO half-life, varying from a few hours to days in summertime, depending on the concentrations of relevant waterborne species (organic matter, NO₃⁻, NO₂⁻, HCO₃⁻).

The solar photocatalysis has received increasing attention in the last years due to its great potential as eco-friendly technology to detoxify wastewater polluted with estrogenic and/or androgenic chemicals. In this context, this study aims to demonstrate the photocatalyzed degradation of two fungicides (vinclozoline and fenarimol) and four insecticides (malathion, fenotrothion, quinalphos, and dimethoate) all of them with endocrine-disrupting activity, in a wastewater effluent under natural sunlight and pilot plant scale. For this, we have combined hydroxyl radical (HO•)- and sulfate radical (SO₄●⁻)-based advanced oxidation processes (AOPs) by using of ZnO as photocatalyst and Na₂S₂O₈ as oxidant, respectively. Previously, catalyst loading, effect of electron acceptor, and pH conditions were optimized using a lab photoreactor under artificial light. As a result, 200 mg L⁻¹ of ZnO and 250 mg L⁻¹ of Na₂S₂O₈ were used in the further experiment at pilot plant scale at pH around 7. The results show that the use of the tandem ZnO/Na₂S₂O₈ strongly enhances the reaction rate of the studied pesticides as compared with the photolytic test. All pesticides followed an apparent first-order degradation curve. The necessary time for 90% degradation (DT₉₀) under sunlight irradiation ranged from 26 to 1000 min (2–75 min as normalized illumination time, t₃₀W) for malathion and fenarimol, respectively. At the end of the lighting, the remaining percentage of dissolved organic carbon (DOC) was up to 92% lower than its initial content and toxicity (Vibrio fischeri) decreased from 65% of inhibition to an acceptable value of 12% at the end of the treatment. A weak increase in the electrical conductivity (EC) was observed due to the mineralization process. The findings confirm the efficacy of the treatment to remove pesticides from wastewater using natural sunlight as renewable energy source, mainly in sunny areas as Mediterranean basin.

Increasing applications of rare earth elements (REEs) and improving technologies have led to increased demand. Because of their limited availability and depletion of most resources, the recovery of these elements from waste has become important. The use of cost-effective materials for this purpose and the high value that can potentially be recovered would be beneficial and attractive to many industries using REEs. In this study, natural zeolite and bentonite were used in batch studies to recover REEs (La, Y, Lu, Sm, Pr, Tm, Ce, Nd, Yb, Gd, Eu, Er, Ho, Dy, and Sc) from aqueous solutions. The effect of adsorbent dosage, pH, concentration, contact time, and competing ions on recovery was investigated. Desorption studies were conducted using ammonium sulphate. Adsorption onto zeolite was found to increase with pH, whereas uniform adsorption was observed for bentonite, except at pH 2 (16% less efficiency). The pH values of 6.2 and 3.2 were selected as the optimum for zeolite and bentonite, respectively. For zeolite, the average adsorption efficiencies for REEs at 0.5, 1.0, 2.0, 5.0, and 10 mg L⁻¹ were found to be 91, 96, 89, 40, and 20% respectively but, > 98% adsorption efficiencies were achieved with bentonite at all concentrations. The zeolite and bentonite adsorption data were better described by Langmuir though, for bentonite, the coefficients of determination (R² values) for the Freundlich and Dubinin-Radushkevich isotherm models were also significant. There was no significant difference (p > 0.05) on the adsorption of the elements in the presence of competing ions. Bentonite proved to perform better, most likely as a result of its higher surface area. Generally, the good adsorption performance of both adsorbents in their natural forms makes them an attractive and potential cheap option for the recovery of REEs from wastewaters.

The aim of this study was to characterize qualitatively and quantitatively the composition of the main rhizodeposits emitted from maize (Zea mays) under Cd stress, in order to discuss their role in Cd availability and tolerance. Maize was grown for 6 weeks in sand at four Cd exposure levels (0, 10, 20, and 40 μM Cd in nutrient solution) and two types of rhizodeposits were collected at the end of cultivation period. Mucilage and other molecules adhering to rhizospheric sand were extracted with a buffer before root exudates were collected by diffusion into water. Total carbon, proteins, amino acids, and sugars were analyzed for both rhizodeposit types and about 40 molecules were identified using GC-MS and LC-MS. Cadmium effect on plant morphology and functioning was slight, but consistent with previous works on Cd toxicity. However, rhizodeposition did tend to be impacted, with a decrease in total carbon, sugars, and amino acids correlating with an increasing Cd content. Such a decrease was not noticeable for proteins in root exudates. These observations were confirmed by the same trends in individual compound contents, although the results were generally not statistically significant. Many of the molecules determined are well-known to modify, whether directly or indirectly, Cd speciation and dynamics in the soil and could play a role in Cd tolerance.

Vehicular evaporative emissions have been recognized as an important source of volatile organic compounds to the environment and are of high environmental concern since these compounds have been associated to the formation of surface ozone and secondary organic aerosols. Evaporative emissions occur during any vehicle operation. In Europe, a revised legislative test procedure has been recently introduced to better control evaporative emissions during parking. However, emissions related to normal driving conditions—the so-called running losses—have received less attention compared with the other categories. The current study aims at giving some insights to the prevailing temperature conditions in fuel tanks of typical European vehicles during normal driving operation. The effects of ambient air temperature, trip duration, vehicle speed, and fuel tank level on the temperature reached by the fuel inside the tank under different real-world operating conditions were studied. Tank temperature can exceed 40 °C depending on ambient and driving conditions. Ambient temperature was found to be the most important parameter affecting the tank temperature. Trip duration and driving pattern may also have an influence on the tank temperature particularly when long trips combined with high vehicle speed are examined. Additionally, the difference between tank and ambient temperature was examined during the individual trips and was found to vary between 1 and 10 °C depending on the testing conditions. The most important parameters affecting the delta temperature were found to be the trip duration and the maximum vehicle speed. Finally, the purging strategy of two of the test vehicles was monitored, and the parameters affecting the purging flow rate were investigated. No strong correlation between the canister flow rate with ambient temperature, vehicle speed, or fuel level was observed in either of the tested vehicles. Substantially different canister flow rate levels between the two vehicles point to different purging strategies.

The quantification of heavy metal contents in soils and their sources are essential for contamination monitoring and the assessment of the potential risks to the ecosystems. This study aims to investigate the source of heavy metals and other elements in soils from a uranium-phosphate deposit using integrated multivariate and geostatistics techniques. For this, 50 soil samples in Itataia deposit, Northeastern, Brazil, were collected at 0–0.2-m depth for the determination of U, Fe, Al, Mn, Ti, Zn, Cu, Ni, Mo, Co, Cr, Cd, Pb, As, Se, V, B, and Zr. The Pb, Se, Ni, Cr, As, and Mo mean contents were closer or exceeded The Brazilian Environmental Council (CONAMA) prevention values for soils. Uranium content was about 500 times higher than the mean levels reported for Brazilian soils. The cluster analysis indicates three geochemical groups based on different contamination levels. The first principal component was associated with lithological origin, the second principal component may be related to anthropogenic sources, and the third and fourth principal components indicated a joined source (natural and anthropogenic), indicating different sources of contamination. Mo was not related to other heavy metals, being found independent in the area. The accumulation of heavy metals in soils is associated not only with the parent material but also with the minerals of the soil. In the area of study, calcareous soils favored alkaline conditions that influenced the dynamics of heavy metals. The multivariate and geostatistical analyses were able to provide preliminary information regarding the metal contents in soil for environmental management.

Particle-induced x-ray emission (PIXE) spectroscopy has been used to characterize soil samples from two relatively old gold mine sites (Iperindo and Itagunmodi) in the Ilesha schist belt of Southwestern Nigeria. This is with a view to identifying the indicator or pathfinder elements of gold for fingerprinting and toxicity potential assessment purposes. Average elemental concentrations of 19 major, minor, and trace elements were determined, and the geochemical data of Mn, Ni, Cu, Zn, Ag, As, Pb, and Au together with multivariate factor and cluster statistical analyses allowed to identify As and Ag as the pathfinder elements of gold. The high concentration of the determined pathfinder elements (As and Ag) as well as other toxic metals (Pb and Cu) implies a relatively high metal contamination risk to the miners and the ecosystem. The major hazard is represented by the abandoned mining wastes, pits, and ponds, already serving as fish ponds.

Tannins are special plant metabolites used in leather processing that act as pollutants. These substances are toxic to aquatic biota and can cause cell rupture. These harmful effects make the treatment of tannery wastewater difficult. Phytoplankton species are community components that are rarely considered in the biodegradation of organic compounds. However, in association with bacteria, these organisms can improve the biodegradation of pollutants by different mechanisms. The aim of the present study was to evaluate the potential of non-axenic cultures of Chlorella vulgaris containing Lactobacillus casei and Synechococcus sp. containing Rhizobium rosettiformans and Sphingomonas koreensis to biodegrade tannic acid (TA). Cultures in BG-11 medium containing TA (250 mg L⁻¹) were incubated under a photoperiod or in the dark and monitored for 96 h. The cultures with added TA grew more than the control cultures under both the photoperiod and dark conditions. A reduction in the TA concentration and the TA metabolite gallic acid was observed under both conditions. Ellagic acid was identified and demonstrated resistance to biodegradation under the evaluated conditions, and neither of the other metabolites was detected. BG-11 culture medium is poor in organic material; therefore, microalgae and cyanobacteria contribute to bacterial metabolism. Under experimental conditions, phytoplankton species seem to contribute to the biodegradation of tannin residues, and in natural environments, they may aid in the bioremediation of sites contaminated by these pollutants.