Accidental river pollution can cause damage to the environment, put at risk the health of people that use the water for domestic purposes, and, not lastly, compromise dependent economic activities (e.g., agriculture). The reduction of the concentration of pollutant on any river following an accidental pollution can be achieved using dilution, by opening for certain duration the bottom gates of the reservoirs placed on the river’s tributaries and releasing a significant volume of clean water in the main river. The hydraulic simulation and the pollutant transport are executed, firstly considering there is no dilution and secondly for the dilution scenario (bottom gates of the reservoirs open). A database was created, containing the results of simulations of pollutant transport for various values of the pollution characteristics in both diluted/undiluted scenarios. The database served for the implementation of a web decision support tool that presents an intuitive and easy to use GUI that allows the user to input details of the accidental pollution. Straightforward actions to be taken are presented to the end-user (e.g., “Open the bottom gates of the reservoir X at time T1 and close it at time T2”) and synchronized charts show the effect of the dilution in respect to the concentration of pollutant at certain locations on the river. Using the described approach, a reduction of pollutant concentration in the river with up to 90% can be obtained.

In this work, the photo-Fenton process at near-neutral pH was applied for the removal of the β-lactam antibiotic oxacillin (OXA) in water using artificial and sunlight. Initially, the main variables of the process (Fe(II), H₂O₂, and light power) were optimized by a statistical factorial design (2³ with center points). The experimental design indicated that 90 μmol L⁻¹ of Fe(II), 10 mmol L⁻¹ of H₂O₂, and 30 W of power light were the favorable conditions for degradation of OXA at 203 μmol L⁻¹. In the photo-Fenton system, the H₂O₂ alone, UV-light/H₂O₂, and Fe(II)/H₂O₂ subsystems presented a significant participation on antibiotic removal. Moreover, based on the primary organic transformation products, a mechanism of OXA degradation was proposed. Under the favorable operational conditions, both the pollutant and the antimicrobial activity were eliminated after 50 min of process application. Although at 480 min of treatment, only 5% of mineralization was achieved, the level of biodegradability of the solutions increased from 0.08 to 0.98. Interestingly, the presence of pharmaceutical additives (glucose, isopropanol, and oxalic acid) had a moderate interference on the efficiency of the pollutant removal. Additionally, the treatment at pilot scale of the β-lactam antibiotic in a pharmaceutical complex matrix using solar radiation allowed the complete removal of the pollutant and its associated antimicrobial activity in a very short time period (5 min). These results evidenced the applicability of the photo-Fenton process to treat wastewaters from pharmaceutical industry loaded with β-lactam antibiotics at near neutral pH values efficiently.

Sulfur dioxide is a major air pollutant in the environment. Fortunately, the plant purification system can effectively reduce SO₂ pollution. However, the effect mechanism of plant purification system for the dynamic evolution of SO₂ remains incompletely clear. In this work, inspired by the “Boston ivy,” we successfully designed and constructed a semi-continuous plant system. Subsequently, based on the “vine-like plant” and the “island-like plant,” the semi-continuous plant system and the isolated plant system are selected as the models of plant purification system, respectively. The dynamic evolution of SO₂ in the plant systems is investigated using the computational fluid dynamic (CFD) method. It is demonstrated that the dynamic evolution of SO₂ is impacted by the plant structure and the flow path ((cg/lg) + (cₗ/lₗ)). In the semi-continuous plant system, the strong flow paths with gradually weakened fluctuation are restricted by this special plant structure, the length of flow paths are extended, and more SO₂ can be dissolved. In the isolated plant system, the mild flow paths with linear relationship can easily pass through the plants, such that only a little SO₂ is dissolved. Overall, the present study opens a new path into the dynamic evolution of SO₂ pollution in the plant systems, which helps providing guidance for the designing of plant purification system.

Toxicities of methylmercury chloride (CH₃HgCl) and methylmercury hydroxide (CH₃HgOH) to cultured neuroblastoma cell line SH-SY5Y in vitro are evaluated. This is the comparative study between two methylmercury compounds to find out the extent of toxicity of these compounds are toxic to SH-SY5Y cell line. Both cytotoxicity and genotoxicity experiments were carried out to find out the more toxic compound. For cytotoxicity study, four staining assay methods independently with trypan blue (TB), acridine orange/ethidium bromide (AO/EB), 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide (MTT), and neutral red (NR) were used and the comet assay method was done for genotoxicity study. The obtained toxicity data were used for probit analysis. In cytotoxicity, CH₃HgCl had minimum inhibitory concentration (MIC) value in each assay method as 3 mg/L invariably; LC₂₅ values were in the range 7.41 to 10.23 mg/L, and LC₅₀ values were 14.79 to 15.48 mg/L; while LC₇₅ values were 20.89 to 26.91 mg/L. Moreover, LC₁₀₀ value was 30 mg/L, known from comet assay experiments for CH₃HgCl. Similarly for CH₃HgOH, the MIC value in each assay method was invariably 3 mg/L, the LC₂₅ values were in the range 12.58 to 16.59 mg/L, and LC₅₀ values were 19.49 to 23.44 mg/L; LC₇₅ values were 27.54 to 30.90 mg/L and LC₁₀₀ value was 42 mg/L in each assay done for cytotoxicity and genotoxicity studies. Computed DNA fragmentation indices in comet assays were 98.6 ± 0.57 30 mg/L with CH₃HgCl and 76 ± 5.29 30 mg/L with CH₃HgOH. This study clearly indicated that methylmercury chloride is more toxic than methylmercury hydroxide to SH-SY5Y cell line. Toxicity of Hg had been quantified with in vitro cultured human neuroblastoma cell line; since it has neurotoxic effects, its neural evaluation has implications in environmental health issues.

This study aimed to explore the application potential of an eco-friendly waste—shrimp shell in Microcystis aeruginosa (M. aeruginosa) control—for the first time. Four treatments with different doses (0.75, 1.5, 3.0, and 6.0 g/L) were built to investigate the effects of shrimp shell on the growth, cell viability, physiological changes, and microcystins (MCs) release of M. aeruginosa cells. The water quality after shrimp shell treatment was also detected. Results showed that the growth of M. aeruginosa was effectively inhibited by shrimp shell, and the inhibition rates were dose-dependent within 7 days. Though shrimp shells at high doses could inhibit the cell growth greatly, the MC release was accelerated as they led to the cells lysis. While with the low shrimp shell dose (0.75 g/L), both satisfied inhibition effect and low MC release could be achieved simultaneously. For the water quality, we found that the turbidity and TN was not affected obviously with low dosage of shrimp shell, but it resulted in the increasing of CODMₙ and TP contents. In summary, the shrimp shell can be used as an effective algicide to control algal blooms but its adverse effect on CODMₙ and TP of water should be further solved.

The Hg²⁺ removal performance of fishbone charcoal prepared from discarded fishbone has been investigated in this work. The XRD, FTIR, and BET results demonstrated that the main composition of fishbone charcoal was hydroxyapatite and the specific surface area was 117 m²/g. The adsorption experiments indicated that fishbone charcoal had an extremely high adsorption capacity for Hg²⁺ (243.77 mg/g). The excellent Hg²⁺ adsorption capacity might be ascribed to the ion exchange of Hg²⁺ to the Ca²⁺ in the structure of fishbone charcoal, complexation of Hg²⁺ with ≡Ca(OH)²⁺ on the surface of fishbone charcoal, as well as electrostatic interaction between electronegative fishbone charcoal surface and cation Hg²⁺. This work transformed kitchen garbage (i.e., fishbone) into an effective mercury adsorbent with considerable capacity, giving a perspective sight for the utilization of solid waste.

Substantial production and wide applications of engineered nanomaterials (ENMs) have raised concerns over their potential influences on the environment and humans. However, regulations of products containing ENMs are scarce, even in countries with the greatest volume of ENMs produced, such as the United States and China. After a comprehensive review of life cycles of ENMs, five major challenges to regulators posed by ENMs are proposed in this review: (a) ENMs exhibit variable physicochemical characteristics, which makes them difficult for regulators to establish regulatory definition; (b) Due to diverse sources and transport pathways for ENMs, it is difficult to monitor or predict their fates in the environment; (c) There is a lack of reliable techniques for quantifying exposures to ENMs; (d) Because of diverse intrinsic properties of ENMs and dynamic environmental conditions, it is difficult to predict bioavailability of ENMs on wildlife and the environment; and (e) There are knowledge gaps in toxicity and toxic mechanisms of ENMs from which to predict their hazards. These challenges are all related to issues in conventional assessments of risks that regulators rely on. To address the fast-growing nanotechnology market with limited resources, four ENMs (nanoparticles of Ag, TiO₂, ZnO and Fe₂O₃) have been prioritized for research. Compulsory reporting schemes (registration and labelling) for commercial products containing ENMs should be adopted. Moreover, to accommodate their potential risks in time, an integrative use of quantitative structure-activity relationship and adverse outcome pathway (QSAR-AOP), together with qualitative alternatives to conventional risk assessment are proposed as tools for decision making of regulators.

Novel magnetite nanoparticles (NPs) modified with pectin coating were fabricated, characterized, and evaluated as potential draw solute in a forward osmosis (FO) process for water desalination applications. The prepared NPs had a spherical shape with an average diameter of 200 nm and saturation magnetization of 23.13 emu/g. Thermogravimetric analysis (TGA) and FTIR spectra elucidated the successful pectin coating on magnetite surface. The potential use of the fabricated NPs in water desalination was conducted via a newly developed lab-scale FO system. Deionized water, saline water (0.2, 0.5, and 1 g% NaCl solution), and real well water (TDS = 0.9 g%) were used as feed solutions. In all experiments, the water flux gradually decreased along with the extension of experimental time and NaCl rejection rate by the FO membrane was measured to be higher than 95%. Moreover, it was found that the pectin-coated magnetite NPs demonstrated to be able to draw clean water across the FO membrane from well water with a remarkable salt rejection of 97%. Thus, it is believed that the proposed FO system using pectin-coated magnetite NPs as draw solute can be a promising technique for desalination of well waters in an environmental-friendly and energy-saving manner.

Activated carbon fiber (ACF) has become an emerging activator for peroxydisulfate (PDS) to generate sulfate radical (SO₄•⁻). However, the relative low activation efficiency and poor contaminant mineralization limited its widespread application. Herein, ultrasound (US) was introduced to the ACF activated PDS system, and the synergistic effect of US and ACF in PDS activation and the enhancement of contaminant mineralization were investigated. The synergistic effect of US and ACF was observed in the PDS activation to decolorize orange G (OG). The decolorization efficiency increased with increasing ACF loading and US power, and PDS/OG ratio from 1 to 40. The activation energy was determined to be 24.065 kJ/mol. The radical-induced decolorization of OG took place on the surface of ACF, and both SO₄•⁻ and hydroxyl radical (•OH) contributed to OG decolorization. The azo bond and naphthalene ring on OG were destructed to other aromatic intermediates and finally mineralized to CO₂ and H₂O. The introduction of US in the ACF/PDS system significantly enhanced the mineralization of OG. The combination of US and PDS was highly efficient to activate PDS to decolorize azo dyes. Moreover, the introduction of US remarkably improved the contaminant mineralization.

Sulfur extraction from fuel is essential to be done for environmental and industrial point of view. Extractive desulfurization (EDS) is one of the most promising techniques in order to achieve legislative sulfur content requirements. Among numerous extractants and solvents, ionic liquids (ILs) are more capable due to their desirable green solvent properties. This work demonstrated that trihexyl(tetradecyl)phosphonium tetrafluoroborate ([THTDP]BF₄) was synthesized, characterized, and employed as extraction solvent for extraction of dibenzothiophene (DBT), thiophene, benzothiophene, and other alkyl-substituted derivatives of sulfur from liquid fuel. Molecular confirmation and purity of synthesized ([THTDP]BF₄) were analyzed with FTIR, Raman, NMR, EPR, UV, TG/DSC, and XRD analyses. Also, physical properties of ([THTDP]BF₄) were carried out. The effects of extraction time, temperature, sulfur compounds, ultra-sonication, and ([THTDP]BF₄) recycling/regeneration on DBT removal from liquid fuel were also examined. DBT removal in n-dodecane was 92.6% using EDS with mass ratio (1:1) in 30 min at 30 °C under the mild reaction conditions. ([THTDP]BF₄) could be reused up to ten cycles for sulfur extraction and regenerated for few more cycles with good DBT removal ability. Also, the sulfur extraction from real fuels and multistage extraction performance were tested. The experimental data and results provided in this article discover the remarkable understandings of tetrafluoroborate-based phosphonium ionic liquids as promising solvent for EDS.