A mixed community of bacteria was enriched from groundwater contaminated with naphthalene as the sole carbon source. Based on the results of 16S rRNA sequences, Acinetobacter and Pseudomonas were the predominant species in the naphthalene-enriched culture. Different initial forms of nitrogen, including nitrate, nitrite, and ammonium, were beneficial to naphthalene degradation, which was considered second-order kinetics and naphthalene could be decreased by 94.68% during the incubation period of 30 days with an initial naphthalene concentration of 0.5 mg/L. These clear biogeochemical denitrification signals, the consumption and accumulation of nitrate, nitrite, and ammonium during the incubation period, suggested that naphthalene degradation may be coupled with denitrification and DNRA metabolism. Nitrate and nitrite were reduced mainly as electron acceptors, and ammonium was utilized by microorganisms as an important inorganic nutrient for their growth and reproduction, which promoted the degradation of naphthalene. The results of this study contributed to the removal pathway and transformational mechanism of nitrogen and reveal their involvement in the anaerobic biodegradation of naphthalene.

As we all know, geochemical data usually contain outliers and they are heterogeneous, which will severely affect the use of receptor models based on classical estimates. In this paper, an advanced modified RAPCS-RGWR (robust absolute principal component scores-robust geographically weighted regression) receptor model was introduced to analyze the pollution sources of eight heavy metals (Cd, Hg, As, Pb, Ni, Cu, Zn) in a city of southern China. The results showed that source identification and source apportionment are more consistent by this advanced model even though the soil types and farming patterns are diverse. Moreover, this model decreased the occurrence of negative values of the source contribution. For these reasons, the pollution sources were classified into five types by the new model in the study area: agricultural sources, industrial sources, traffic sources, comprehensive sources, and natural sources. (1) The contributions of agricultural sources to Cr and Ni were 243.36% and 242.61%, respectively; (2) the contribution of industrial sources to Cd was 79.25%; (3) the contribution of traffic sources to Cu was 100.31%; (4) the contributions of comprehensive sources to Hg, Pb, and Zn were 253.90%, 242.31%, and 93.32%, respectively; and (5) the contribution of natural sources to As was 208.21%. Overall, the RAPCS-RGWR receptor model improved the validity of the receptor models. It is of great realistic significance to understand and popularize the advanced model in soil source apportionment in agricultural land.

Thermal processing of materials is used in a very broad sense to cover all sets of technologies and processes for a wide range of industrial sectors and it refers to material development with a specific application potential due to its advantages over conventional synthesis methods. By applying hydrothermal technique, the development of advanced materials has been pursued, in order to retain heavy metals from wastewater. This research refers to nanosilica-based materials, specifically mesoporous silica, for which the heavy metal retention properties were improved by using nano-TiO₂ and nano-CeO₂, considering the properties of titanium and cerium. Advanced methods have been used to characterize the materials obtained as X-ray fluorescence (XRF) and energy-dispersive X-ray spectroscopy (EDS) for chemical composition; X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for microstructural properties and BET analyser for pores and specific surface area characterization. The results showed higher retention efficiencies for the doped nanosilica.

A bibliometric method was used to evaluate the global scientific publications about sulfur oxides and nitric oxides released by coal-fired flue gas and vehicle exhaust from 1995 to 2018 and to provide insights into the characteristics of the articles and tendencies that may exist in the publications. Performance of publications, research tendency, and hotspots were analyzed. The article number had an explosive growth in 2004 and, then, began to grow steadily. China had an absolutely advantage in publication quantities; however, America had a leading position considering publication cited times. The simultaneous removal of mercury, particulate matter, and CO₂ was a research hotpot in sulfur oxide and nitric oxide control process; oxidation, absorption, and catalytic reduction were the central control methods that had the most strength in relation with sulfur dioxide and nitric oxide. Considering the study of traditional flue gas pollutant control method (limestone-gypsum method, selective catalytic reduction, etc.) was perfection, it was speculated that adsorption by ionic liquid, electricity charging, advanced oxidation progress, and multi-pollutant removal, simultaneously, would be the new research orientation in flue gas pollutant control. One of the hot points of controlling the vehicle exhaust was the application of the “green energy” biodiesel; lots of keywords concerning human health suggested that quite a lot studies were focused on the health hazard brought by sulfur oxides and nitric oxide.

Carboxymethyl cellulose–stabilized sulfidated nano zerovalent iron (CMC-S-nZVI) was tested for its capacity to the removal of Cr(VI) in this study. The effect of synthesis approaches on morphology and properties of CMC-S-nZVI was studied. Results revealed CMC-S-nZVI prepared by the surface corrosion method had favorable homogeneity and corrosion resistance. The structure and morphology of CMC-S-nZVI particles were investigated by transmission electron microscopy, X-ray powder diffraction, and Fourier-transform infrared spectrometry. Batch experiments showed that the removal efficiency of Cr(VI) by the CMC-S-nZVI particles was influenced by the S/Fe molar ratio, initial pH, initial Cr(VI) concentration, and the reaction temperature. Increasing S/Fe molar ratio from 0 to 0.35 enhanced Cr(VI) removal efficiency from 65.37 to 85.08%. Reducing pH value and improving the reaction temperature have a positive impact on Cr(VI) removal. The removal amount was 535 mg/g (total iron) CMC-S-nZVI with initial Cr(VI) concentration of 50 mg/L. Compared with CMC-nZVI, CMC-S-nZVI had better performance in Cr(VI) removal in a simulated groundwater system. The results indicated that CMC-S-nZVI might be applicable for in situ treatment of the Cr(VI)-containing groundwater.

The aim of the present study was to isolate several bacterial consortia from a soil sample and to establish if they could colonize zirconium-tin alloy, such as Zircaloy-4. Two bacterial consortia containing aerobic heterotrophic bacteria and anaerobic sulfate-reducing bacteria were isolated from a soil sample. The aerobic heterotrophic bacteria exhibited a higher capability to utilize different sole carbon sources, as compared with anaerobic sulfate-reducing bacteria. Based on a morphological, biochemical, and molecular analysis, bacterial isolates were identified as Pseudomonas putida IBBHA₁, Pseudomonas aeruginosa IBBHA₂, Achromobacter spanius IBBHA₃, Citrobacter freundii IBBSR₁, Citrobacter youngae IBBSR₂, and Citrobacter braakii IBBSR₃. Isolated bacterial consortia which possess distinct DNA fingerprints were able to form biofilms and colonize the surface of zirconium-tin alloy coupons, although the colonization of coupons by the aerobic heterotrophic bacteria or anaerobic sulfate-reducing bacteria alone was lower compared with that observed when the coupon was immersed in a mixture of both bacterial consortia. Coupons immersed in these bacterial consortia revealed changes in the surface characteristics, which can facilitate or accelerate zirconium-tin alloy corrosion. The accumulation of corrosion products on coupons surface was less significant when the coupons were immersed solely in aerobic heterotrophic bacteria or anaerobic sulfate-reducing bacteria, compared with that observed when the coupon was immersed in a mixture of both bacterial consortia.

Analysis of limnic sediments can serve as a tool to assess sedimentary pollution for both the status quo as well as changes over time. However, in environmental studies, often only a small number of established well-studied contaminants are considered. This study focused on a more comprehensive investigation of sedimentary pollution of Djerdap Reservoir. Therefore, complementary analytical approaches were applied covering lipophilic organic contaminants and heavy metals. Investigations were performed on limnic sediment layers representing a period of 43 years of reservoir functioning. The core was sectioned on 11 samples and analyzed for, loss on ignition (LOI), and organic compounds (gas chromatography-mass spectrometry). Here, we report the quantitative data of 43 lipophilic organic compounds indicating both domestic and industrial emissions. Measured concentrations are generally low. Surprisingly, no polychlorinated biphenyls have been detected. Data concerning grain size, sedimentological, and inorganic composition were measured and published by in Kasanin-Grubin et al. (Kasanin-Grubin et al. 2019).

The pharmaceuticals acetaminophen, sulfamethoxazole, and carbamazepine, and herbicide atrazine are among the most highly manufactured compounds in the world and are frequently detected in the aquatic environment. Much uncertainty exists regarding the impacts of the pharmaceuticals on non-target aquatic resources, while more is known about atrazine. Reduction of residues of each chemical in surface water will reduce the exposures that organisms experience in the surface water environment, thus reducing unknown risks. This project evaluated the potential use of two aquatic plant species (Acorus gramineus and Canna hybrida ‘Orange Punch’) for reducing concentrations of the chemicals in water. Concentrations of each contaminant in solution were reduced in the presence of the plants after 14 days of exposure, in (acetaminophen 64–100%, atrazine 32–51%, carbamazepine 26–49%, sulfamethoxazole 41–60%). Results indicate that these plants have potential for reducing concentrations of these chemicals in surface water, but that plant- and chemical-specific properties prevent making generalizations regarding the extent and pathways for dissipation.

This paper presents an experimental study of suspended particle transport through sand layer using a new self-developed sand layer transportation-deposition testing system, and the study aims to identify the effects of temperature on the transport of suspended particles through porous medium. Four typical temperatures (5 °C, 15 °C, 25 °C, and 35 °C) were considered in our study, and the experiments were conducted under four size compositions and three flow velocities (1.5 cm/s, 0.2 cm/s, and 0.04 cm/s). The tests were conducted using quartz sand as the porous medium and quartz powder as particles to monitor the change in turbidity under the different conditions. The breakthrough curves were analyzed, and the results demonstrated that changes in temperature can affect the breakthrough curves, especially at the peak. The influence is particularly significant under lower flow velocities and for smaller particles. In regard to the influence factors on the transport process, water viscosity and adsorption effect can be regarded as promoting factors, while kinetic energy of particles can be classified as constraining factors.

This study aimed at investigating the degradation of fungicide carbendazim (CBZ) via photo-Fenton reactions in artificially and solar irradiated photoreactors at laboratory scale and in a semi-pilot scale Raceway Pond Reactor (RPR), respectively. Acute toxicity was monitored by assessing the sensibility of bioluminescent bacteria (Aliivibrio fischeri) to samples taken during reactions. In addition, by-products formed during solar photo-Fenton were identified by liquid chromatography coupled to mass spectrometry (UFLC-MS). For tests performed in lab-scale, two artificial irradiation sources were compared (UVλ > ₂₅₄ₙₘ and UV-Visλ > ₃₂₀ₙₘ). A complete design of experiments was performed in the semi-pilot scale RPR in order to optimize reaction conditions (Fe²⁺ and H₂O₂ concentrations, and water depth). Efficient degradation of carbendazim (> 96%) and toxicity removal were achieved via artificially irradiated photo-Fenton under both irradiation sources. Control experiments (UV photolysis and UV-Vis peroxidation) were also efficient but led to increased acute toxicity. In addition, H₂O₂/UVλ > ₂₅₄ₙₘ required longer reaction time (60 minutes) when compared to the photo-Fenton process (less than 1 min). While Fenton’s reagent achieved high CBZ and acute toxicity removal, its efficiency demands higher concentration of reagents in comparison to irradiated processes. Solar photo-Fenton removed carbendazim within 15 min of reaction (96%, 0.75 kJ L⁻¹), and monocarbomethoxyguanidine, benzimidazole isocyanate, and 2-aminobenzimidazole were identified as transformation products. Results suggest that both solar photo-Fenton and artificially irradiated systems are promising routes for carbendazim degradation.