In this paper, a magnetic nano-Fe₃O₄/triethanolamine/GO composite (TEA-GO-FE) was prepared by using graphene oxide (GO), triethanolamine (TEA), and ferric chloride. The result indicates that triethanolamine acted as an important role for the growing of Fe₃O₄ and adsorption ability of composite material. The synthesis mechanism of TEA-GO-FE was investigated through the medium of SEM-EDS, XRD, FT-IR, and TEM. The characterization results indicated Fe₃O₄ nanoparticles have been successfully loaded on the surface of graphene oxide and they were encapsulated by TEA and have excellent stability. According to the results of XRD, the general particle size of Fe₃O₄ on TEA-GO-FE was 27.5 nm. In order to understand the adsorption properties of TEA-GO-FE for Pb²⁺ and Cu²⁺, this article uses a static adsorption study method. The optimized adsorption conditions are as follows: pH = 5.0, temperature is 293.15 K, and the ion concentration is 100 mg/L. Under the optimized prerequisites, the adsorption capacities of Pb²⁺ and Cu²⁺ were 121.5 mg/g and 68.7 mg/g, separately. Through thermodynamic as well as kinetic studies, the adsorption process of Pb²⁺ and Cu²⁺ on TEA-GO-FE is a self-heating process.

Actinomycetes are a group of the Gram-positive bacteria famous for their antimicrobial, anticancer, anti-parasitic, and anti-inflammatory activities. This study aimed to investigate the efficacy of two bacterial extracts derived from two soil actinomycete strains (S19 and G30) against carbon tetrachloride (CCl₄)–induced nephrotoxicity in experimental rats. Sixty-four male rats were assigned to four groups of 16 rats in each group. The 1st group was kept as a normal (control) group and given corn oil combined with the used production medium, while the 2nd group received only CCl₄ (CCl₄ group). On the other hand, the 3rd group (CCl₄+S19) was administered CCl₄ and the extract of the actinomycete strain S19 and the 4th group (CCl₄+G30) received CCl₄ and the extract of the actinomycete strain G30, both treatments for 8 weeks. The results revealed that the two actinomycete extracts S19 and G30 could significantly (p < 0.01) lower the elevated levels of serum creatinine, urea, and uric acid caused by the CCl₄ administration. Additionally, the two actinomycete extracts improved the decreased serum total protein. Interestingly, treatment of the CCl₄-intoxicated rats with S19 and G30 extracts remarkably reversed the lowered renal glutathione (GSH), glutathione peroxidase (GSH-Px), peroxidase (Px) and superoxide dismutase (SOD) activities, and the elevated lipid peroxidation (LPO) levels. The histopathological examination of the treated kidney revealed that the two actinomycete extracts improved rats against CCl₄-induced kidney lesions. The present results suggested that the protective effect of the two actinomycete extracts may rely on its effect on reducing the oxidative stress and improving the antioxidant defense system.

This batch and column kinetics study of arsenic removal utilized copper-impregnated natural mineral tufa (T–Cu(A–C)) under three ranges of particle size. Non-competitive kinetic data fitted by the Weber–Morris model and the single resistance mass transfer model, i.e., mass transfer coefficient kfa and diffusion coefficient (Dₑff) determination, defined intra-particle diffusion as the dominating rate controlling step. Kinetic activation parameters, derived from pseudo-second-order rate constants, showed low dependence on adsorbent geometry/morphology and porosity, while the diffusivity of the pores was significant to removal efficacy. The results of competitive arsenic adsorption in a multi-component system of phosphate, chromate, or silicate showed effective arsenic removal using T–Cu adsorbents. The high adsorption rate—pseudo-second-order constants in the range 0.509–0.789 g mg⁻¹ min⁻¹ for As(V) and 0.304–0.532 g mg¹ min¹ for As(III)—justified further application T–Cu(A–C) in a flow system. The fixed-bed column adsorption data was fitted using empirical Bohart–Adams, Yoon–Nelson, Thomas, and dose–response models to indicate capacities and breakthrough time dependence on arsenic influent concentration and the flow rate. Pore surface diffusion modeling (PSDM), following bed-column testing, further determined adsorbent capacities and mass transport under applied hydraulic loading rates.

Environmental pollution can cause metal accumulation in aquatic organisms, but information on metal bioaccumulation in wild fish from coal mining areas is limited. We investigated tissue-specific metal accumulation in six economically important fish species common to Gaotang Lake, China, located in a coal mining area. We also conducted an assessment of potential risks to human health from consumption of these fish. Mean concentrations of arsenic, cadmium, cobalt, copper, mercury, lead, and antimony in the muscle of six fish species were below the corresponding Chinese maximum allowable concentrations except chromium and generally comparable with levels in fish reported by other studies. Tissue distribution patterns suggested that chromium and mercury were easily transported to the muscle, but concentrations of the other six metals were higher in the liver and gills. The daily intake of each metal was estimated at 0.002–0.220 g/day/kg body weight, and the non-carcinogenic health risks associated with the consumption of the fish from Gaotang Lake were acceptable. The results suggest that metal bioaccumulation in wild fish is not high in this coal mining area.

Carbon materials, as effective adsorbents to numerous aqueous cationic contaminants, have been hardly applied to remove anions in wastewater. In this work, different modifying agents were used to modify corncob biochars (CC) and the surface potentials of these modified biochars were determined. Based on the findings, modification principle was determined to reveal the relationship between surface potentials of the biochars and their nitrate adsorption capacities. The surface potential was dominated by the metal cations and multivalent cations led to even positive zeta potential. The formation of metal oxide not only led to the augment in surface area but also increase the surface charge. FeCl₃-modified biochar (Fe-CC) with the highest positive surface charge was utilized to remove anions (nitrate) from aqueous solutions. Characterization results confirm that Fe₂O₃ structure were successfully formed on biochar surface. This led to the formation of iron nitrate hydrate (Fe(NO₃)₃·9H₂O), which enabled higher nitrate adsorption performance than that of pristine biochar. Batch experiments showed that nitrate adsorption on the Fe-CC was stable and almost independent of experimental pH and temperature. Based on the Langmuir model results, the maximum nitrate adsorption capacity of Fe-CC was 32.33 mg/g. Coexisting anions had negative influence on the adsorption performance. Findings of this work suggest that the modified biochar can be used in wastewater treatment to remove anions such as nitrate. Graphic abstract ᅟ

In this work, fast sequential determination and chemical speciation analysis of inorganic arsenic and antimony in airborne particulate matter collected in outdoor and indoor environments using slurry sampling and detection by hydride generation atomic absorption spectrometry (HG-AAS) is proposed. A Doehlert design was applied to optimise the hydride generation conditions of As and Sb for fast sequential determination in the same aliquot of particulate matter samples after preparation of the slurry. The limits of quantification (LoQ) obtained for As and Sb were 0.3 and 0.9 ng m⁻³, respectively. The accuracy of the analytical method was confirmed by analysis of the certified reference material of urban particulate matter (SRM NIST 1648a), presenting concordance with certified values of 92.7±7.7% for As and 91.2±9.5% for Sb. Precision was expressed as relative standard deviation (% RSD, n=3), with our results presenting values better than 3.4% and 4.2% for total inorganic As and Sb, respectively. For all analysed samples, total As concentrations and its inorganic species were below the LoQ of the analytical method (<0.3 ng m⁻³). However, the averages of total inorganic Sb concentrations in airborne particulate matter, collected as total suspended outdoor particles (TSPₒᵤₜdₒₒᵣ), inhalable particulate matter (PM₁₀), and total suspended indoor particles (TSPᵢₙdₒₒᵣ), were 3.1±0.5, 2.4±0.6, and 2.6±0.4 ng m⁻³, respectively. Trivalent Sb (Sb³⁺) was the predominant inorganic species in all samples investigated, with mean percentages of 76%, 72%, and 73% in TSPₒᵤₜdₒₒᵣ, PM₁₀, and TSPᵢₙdₒₒᵣ, respectively. The presence of Sb and its predominant inorganic form (Sb³⁺) can be attributed to vehicular traffic close to the sampled urban areas. Therefore, fast sequential determination of As and Sb and their inorganic species in particulate matter samples prepared as slurry by FS-HG-AAS is an efficient, accurate, and precise method and can be successfully applied to routine analysis.

A novel non-toxic hybrid BiVO₄-GO-TiO₂-polyaniline (PANI) (BVGT-PANI) composite with superior photocatalysis was successfully prepared via a one-pot hydrothermal reaction. The structural and morphological characterizations of the synthesized compounds were analyzed by a series of techniques. We found excellent photocatalytic efficiencies for methylene blue (MB) and phenol degradation under visible light irradiation after adhering the PANI to the photocatalyst. The degradation rates of MB and phenol reach up to approximately 85% and 80%, respectively, after 3 h of irradiation. For photodegradation MB, BVGTA exhibit the highest kₐₚₚ rate constant of about 1.06 × 10⁻² min⁻¹, which is about 1.63-fold faster than BVG and 2.94-fold faster than BVGT. For photodegradation of phenol, BVGTA exhibits the highest kₐₚₚ rate constant, of about 8.86 × 10⁻³min⁻¹, which is about 1.2-fold faster than BVG and 1.96-fold faster than BVGT. Furthermore, vitro toxicity test against Bacillus subtilis and Staphylococcus aureus demonstrated that the nanophotocatalyst is non-toxic.

The use of banana peel as a sustainable and low-cost precursor for the fabrication of effective biochar was exploited. Here, calcined magnetic biochar (CMB) was fabricated and characterized. CMB possesses surface acidic functional groups (–OH and COO⁻), porous structures, high saturation magnetization (39.55 emu/g), and larger surface area than the non-magnetic biochar (CB). The CMB adsorption performance (72.8, 75.9, and 83.4 mg/g for Zn²⁺, Cu²⁺, and Hg²⁺, respectively at pH 6) in a single component was described suitably by pseudo-second order kinetic model, Langmuir, and Redlich-Peterson adsorption isotherms. Notably, the selectivity factor values in the extended Langmuir isotherm indicated that CMB has higher adsorption affinity toward Hg²⁺ than Cu²⁺ and Zn²⁺ in the multi-component system. Owing to its high adsorption efficiency and fast and easy separation, the calcined magnetic biochar is considered promising and effective for the purification of heavy metal–bearing wastewater.

Complex land use patterns and intense human activities significantly affect the spatial distribution of heavy metals in soils. This is especially true in peri-urban areas. The land use in peri-urban areas is complex and the risk of heavy metal pollution is relatively high. Identifying the correlations between land use patterns and spatial distribution of heavy metals in peri-urban soils is important for enhancing soil security and sustaining soil ecosystem services in areas undergoing rapid urbanisation. In this study, soil samples were collected from 82 experimental sites in a typical peri-urban watershed in eastern China. Copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), arsenic (As), chromium (Cr), lead (Pb) and mercury (Hg) concentrations at different soil depths were analysed. Results showed that heavy metal concentrations in peri-urban soils were significantly affected by land use type and varied with soil depth. Farmland had the highest heavy metal concentrations, whereas forestland had the lowest concentrations; the concentrations in soils decreased with increasing soil depth. Spatial analysis of heavy metals in soils showed that their concentrations rapidly increased with the increasing percentage of town areas in buffer zones. This indicated that land use structure influenced the heavy metal concentrations in peri-urban soils and the influences were correlated to the locations of towns and villages. Correlation analysis showed that Cu, Zn, Cd, Pb and Hg concentrations in soils were significantly affected by altitude, distance from roads, distance from towns and villages and soil clay content. Interestingly, historic land use was also found to affect heavy metal concentrations in forestland. These results can provide scientific guidance for designing effective soil management practices for peri-urban areas.

Crocin (C₄₄H₆₄O₂₄) is an isolated bioactive molecule of saffron extract. It has different pharmacological effects such as antioxidant and anti-inflammatory activities. In the present study, radioprotective property of crocin was investigated in the rat liver. Thirty-two rats were equally divided into four groups: (1) control (normal saline), (2) crocin (200 mg/kg), (3) γ-rays (6Gy), and (4) crocin plus γ-rays-treated groups. The liver histopathology, serum transaminases (ALT and AST), alkaline phosphatase (ALP), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and hepatic lipid peroxidation, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) have been assessed. The histopathological result of hepatic tissue in group 3 showed hydropic degeneration and this progressed to focal or spotty necrosis through the lobule. Moreover, some sinusoids are distended with blood or with leukocytic infiltrations. Other cases in group 3 showed periportal leukocytic infiltrations and necrosis extended out from the portal tract to involve hepatic lobules with fibrinous necrosis in portal vessels, while the examination of hepatic tissues of group 4 showed reduced deformities, irregular arrangement, congested hepatic vessels, and necrosis in hepatocytes. The results also showed significant decreased level of liver function activities, inflammatory markers, lipid peroxidation, and increased levels of liver antioxidants enzymes in group 4. Crocin showed moderate protective effect against γ-rays-induced liver toxicity. The antioxidant effect of crocin may be a major reason for its positive impact on liver parameters. Graphical abstract .