In this study, graphene-based adsorbent was successfully prepared following a thermal treatment method. The prepared material, named as graphene-coated sand (GCS), was used as an adsorbent for the removal of Hg(II) ions from aqueous solutions. Structure, composition, and morphology of the GCS were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffractometer (XRD), Raman spectroscopy, electron diffraction (ED) measurements, energy dispersive X-ray spectroscopy (EDX), surface area measurements, particle size, and zeta potential measurements, respectively. A batch adsorption method was used to assess the ability of GCS towards removal of Hg(II) ions from aqueous solutions. The results of batch studies revealed that the GCS required a pH value 6.0, contact time 120 min, and adsorbent dose of 200 mg to attain adsorption equilibrium. Langmuir, Freundlich, Temkin, and D-R adsorption isotherm models were employed to evaluate the isotherm constants and other parameters related to the adsorption process. The Hg(II) ions uptake by the GCS was found to follow Freundlich isotherm model with R ² value of 0.97695, under optimized conditions and at 40 °C with a maximum adsorption capacity of 299.40 mg/g. The adsorption process followed the second-order kinetic path. The thermodynamic parameters such as ΔH°, ΔS°, and ΔG° were also calculated which suggested that the adsorption processes of Hg(II) ions onto the GCS was endothermic and entropy favored. The values of ΔG° at 283, 303, and 313 K were − 1.10, − 0.025, and − 4.55 kJ, respectively, and ΔH°, ΔS° were calculated to be 26.60 kJ mol⁻¹ and ΔS° 1.35 J mol⁻¹ K⁻¹, respectively. The obtained results revealed that the prepared materials could be effectively and economically beneficial.

We demonstrated a method to form magnetic antimicrobial POHABA (poly-N,N′-[(4,5-dihydroxy-1,2-phenylene)bis(methylene)]bisacrylamide)-based core-shell nanostructure by free-radical polymerization of OHABA on the Fe₃O₄ core surface. The magnetic antimicrobial agent Fe₃O₄@POHABA can be used in domestic water treatment against bacterial pathogens. The thickness of POHABA shell could be controlled from 10.4 ± 1.2 to 56.3 ± 11.7 nm by the dosage of OHABA. The results of antimicrobial-activity test indicated that POHABA-based core-shell nanostructure had broad-spectrum inhibitory against Gram-negative, Gram-positive bacteria and fungi. The minimum inhibitory concentration (MIC) values of Fe₃O₄@POHABA nanostructure against Escherichia coli and Bacillus subtilis were both 0.4 mg/mL. Fe₃O₄@POHABA nanostructures responded to a permanent magnet and were easily recycled. Fe₃O₄@POHABA nanoparticles retained 100% antimicrobial efficiency for both Gram-negative and Gram-positive bacteria throughout eight recycle procedures.

Volatilization is a critical pathway for herbicide loss from agricultural fields, and subsequently deposited downwind from the edge of the field. To better understand the volatilization process, field-scale turbulent volatilization fluxes of metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl) acetamide) were quantified for 13 consecutive years using a combination of herbicide concentration profiles and eddy diffusivities derived from turbulent fluxes of heat and water vapor. Site location, type of herbicides, and agricultural management practices remained unchanged during this study in order to evaluate the effect of soil moisture on metolachlor volatilization. Twenty gravimetric surface soil moisture samples (0–5 cm) were collected immediately after herbicide application and then at 0430 hours each morning to determine the impact of surface moisture on herbicide volatilization. Five days after application, cumulative herbicide volatilization ranged from 5 to 63% of that applied for metolachlor. Metolachlor volatilization remained an important loss process more than 5 days after application when the soil surface was moist. Conversely, if the soil surface was dry, negligible volatilization occurred beyond 5 days. Furthermore, the total amount of metolachlor volatilized into the atmosphere increased exponentially with surface soil water content during application (r ² = 0.78). Metolachlor volatility was found to be governed largely by surface soil moisture.

Bisphenol B (BPB) exhibited higher estrogenic activity and anti-androgenic effects than bisphenol A (BPA) in vitro assays. This result indicates that BPB has higher priority for entry into expensive and stressful testing on animals. However, the disrupting mechanisms of BPB on steroid hormone signaling pathway by in vivo assay have not been investigated yet. In this study, the potential disrupting mechanisms of BPB on the hypothalamic–pituitary–gonadal (HPG) axis and liver were probed by employing the Organization for Economic Co-operation and Development (OECD) 21-day short-term fecundity assay with zebrafish. We found that BPB exposure (1 mg/L) could impair the reproductive function of zebrafish and decline the egg numbers, hatching rate, and survival rate. This finding is related to modifications of the testis and ovary histology of the treated zebrafish. The homogenate T levels in male zebrafish decreased in a concentration-dependent manner, and the E2 level significantly increased when exposed to 0.01, 0.1, and 1 mg/L BPB. Real-time polymerase chain reaction (PCR) was performed to examine the gene expressions in the HPG axis and liver. Hepatic vitellogenin (vtg) expression was upregulated in all exposure males, suggesting that BPB possesses estrogenic activity. The disturbed hormone balance was contributed by the significant alteration of the genes along the HPG axis. These alterations suggest that BPB can lead to adverse effects on the endocrine system of teleost fish, and these effects were more prominent in males than in females.

PCDD/F-contaminated soil of a coastal region formerly involved in the production of pentachlorophenol (PCP) in Tainan City in southern Taiwan, has drawn wide concern throughout the island. This main goal of this study was to find an effective and environmentally friendly means of removing PCDD/Fs from its contaminated fields. We performed a soil washing experiment with fish extract using a combination of ultrasonification and mechanical double-blade stirring. The experiments were conducted under ambient temperature, at a soil/liquid ratio of 1:2.5, 700 rpm, and over a short duration. This combined method using fish extract removed 94.12% of the pollutant in moderately contaminated soils (5 washing cycles) and 94.51% in highly contaminated soils (10 washing cycles), mostly via particle collision and penetration. These findings highlight the benefits of PCDD/F partitioning between the particles and fish oil extract. This study is the first to use fish oil extract, a natural solvent, to treat soils highly contaminated with dioxins. Because fish oil extract is rich in non-toxic bio-surfactants (e.g., alcohols, acids, ketones, etc.), it may be used in this process to improve bioavailability and bioactivity of the soil making bio-attenuation and full remediation safer and more efficient.

Petroleum hydrocarbon, a complex mixture including aliphatic and aromatic hydrocarbons, is known to have negative effects on the environment. We determined the effectiveness of persulfate (PS) (5% w/w) activated using 1% (w/w) of various types of soil minerals, goethite (α-FeOOH), hematite (Fe₂O₃), magnetite (Fe₃O₄), maghemite (γ- Fe₂O₃), manganese oxide (MnO₂), and zeolite (clinoptilolite) to treat petroleum hydrocarbon-contaminated soil. Total petroleum hydrocarbon (TPH) was 4200 ± 124 mg kg⁻¹. The TPH removal efficiency was in the order: Fe₃O₄ > MnO₂ > γ-Fe₂O₃ > Fe₂O₃ > α-FeOOH > clinoptilolite. When the PS dosage and the moisture content of the soil increased, the degradation rate (k ₒbₛ) of TPH removal increased; on the other hand, lowering the pH increased the k ₒbₛ of TPH removal. The PS oxidation of TPH was optimized using response surface methodology (RSM). The interactive effects of three factors, namely, persulfate dosage (X ₁), pH (X ₂), and soil moisture content (X ₃), were investigated. The optimum removal of TPH by PS oxidation activated using 1% (w/w) magnetite was obtained at 5.5% (w/w) PS and 85% (w/w) moisture content at an initial pH of 4.5. However, the soil treated by PS showed a negative effect on soil health. The germination of mung bean (Vigna radiata (L.) R. Wilczek) and the CO₂ release for the treated soil were low, indicating that toxicity had occurred in the treated soil. To restore the treated soil, adding a soil amendment, like CaCO₃, fly ash, or crop residue, was able to improve plant growth and soil microbial activity.

In the present study, the immobilizing fermentation characteristics and o-chlorophenol biodegradation of Rhodopseudomonas palustris using mycelial pellets as a biomass carrier were investigated. To improve the o-chlorophenol degradation efficiency of the combined mycelial pellets, eight cultivation variables including glucose concentration, yeast extract concentration, spore inoculum size, pH, and agitation speed were optimized with an integrated strategy involving a combination of statistical designs. First, Plackett-Burman experiments identified glucose, yeast extract, and spore inoculum size as three statistically significant factors important for o-chlorophenol removal. Then, the steepest ascent method was used to access the optimal region of these significant factors. Finally, response surface methodology by Box-Behnken optimization was used to examine the mutual interactions among these three variables to determine their optimal levels. The ideal culture conditions for maximum o-chlorophenol removal according to a second-order polynomial model were as follows: 15.60 g/L glucose, 3.09 g/L yeast extract, and 9% (v/v) spore inoculum size, resulting in an expected o-chlorophenol removal rate of 92.60% with an o-chlorophenol initial concentration of 50 mg/L and 96-h culture time. The correlation coefficient (R ² = 0.9933) indicated excellent agreement between the experimental and predicted values, whereas a fair association was observed between the predicted model values and those obtained from subsequent experimentation at the optimized conditions.

Basil (Ocimum basilicum L.) is extensively cultivated as either an important spice and food additive or a source of essential oil crucial for the production of natural phenylpropanoids and terpenoids. It is frequently attacked by fungal diseases. The aim of the study was to estimate the impact of thiuram contact time on the uptake of manganese, cobalt, nickel, copper, zinc, cadmium, and lead by Ocimum basilicum L. The relevant plant physiological parameters were also investigated. Two farmland soils typical for the Polish rural environment were used. Studies involved soil analyses, bioavailable, and total forms for all investigated metals, chlorophyll content, and gas exchange. Atomic absorption spectrometry was used to determine concentration of all elements. Analysis of variance proved hypothesis that thiuram treatment of basil significantly influences metal transfer from soil and their concentration in roots and aboveground parts. This effect is mostly visible on the 14th day after the fungicide administration. Thiuram modifies mycoflora in the rhizosphere zone and subsequently affects either metal uptake from the soil environment or their further migration within the basil plant. Notable, those changes are more evident for basil planted in mineral soil as compared to organic soil with higher buffering capacity.

Batch experiments were conducted to study the effect of freeze-thaw frequency on the adsorption behavior of Pb²⁺ and Cd²⁺ and its related mechanisms. The results indicated that the adsorption capacities of Pb²⁺ and Cd²⁺ to the freeze-thaw treated soil were lower than those to the unfrozen soil, and with increasing freeze-thaw frequency, the adsorption capacities of them decreased. These were attributed to the fact that freeze-thaw cycles reduced pH value, CEC, organic matter content, and free iron oxide content of soil, and these soil properties presented negative correlations with freeze-thaw frequency. Freeze-thaw cycles reduced specific adsorption capacities of Pb²⁺ and Cd²⁺ and enhanced nonspecific adsorption ratios of Pb²⁺ and Cd²⁺ compared with the unfrozen soil. The higher freeze-thaw frequency, the higher nonspecific adsorption ratio was. However, the relationship between specific adsorption capacities of Pb²⁺ and Cd²⁺ and freeze-thaw frequency was opposite. Furthermore, the adsorption processes to the unfrozen and freeze-thaw treated soils were spontaneous, for Pb²⁺, its adsorption to soil was endothermal process, for Cd²⁺, on the contrary.

Simultaneous power generation and fecal wastewater treatment were investigated using a combined ABR-MFC-MEC system (anaerobic baffled reactor-microbial fuel cell-microbial electrolysis cell). The installation of multi-stage baffles can benefit retaining the suspended solids in the system and help separate the hydrolysis-acidification and the methanogen processes. The efficiencies of the nitrification-denitrification process were improved because of the weak current generation by coupling the microbial electrochemical device (MFC-MEC) with the ABR unit. Maximum removal rates for chemical oxygen demand (COD) and ammonia nitrogen (NH₄ ⁺-N) were 1.35 ± 0.05 kg COD/m³/day and 85.0 ± 0.4 g NH₄ ⁺-N/m³/day, respectively, while 45% of methane (CH₄), 9% of carbon dioxide (CO₂), and 45% of nitrogen gas (N₂) contents in volume ratio were found in the collected gas phase. An average surplus output voltage of 452.5 ± 10.5 mV could be achieved from the combined system, when the initial COD concentration was 1500.0 ± 20.0 mg/L and the initial NH₄ ⁺-N concentration was 110.0 ± 5.0 mg/L, while the effluent COD could reach 50.0 mg/L with an HRT of 48 h. The combined process has the potential to treat fecal wastewater efficiently with nearly zero energy input and a fair bio-fuel production.