Water pollution caused by Cr(III) is a serious environmental problem which bring adverse effect to environmental protection and public safety. Efficient removal of Cr(III) from aqueous solution is important for the remediation of Cr(III) pollution. Herein, a series of silica-gel/polyamidoamine (PAMAM) dendrimer hybrid materials (SG-G0~SG-G4.0) were used for the removal of Cr(III) from aqueous solution. The factors that affect the adsorption were extensively studied and the adsorption mechanism was demonstrated based on the experimental results and density functional theory (DFT) calculation. Result demonstrates the adsorption capacity of ester-terminated silica-gel/PAMAM dendrimers follow the order of SG-G2.5 > SG-G3.5 > SG-G1.5 > SG-G0.5, while that of amino-terminated ones decrease in the order of SG-G2.0 > SG-G4.0 > SG-G3.0 > SG-G1.0 > SG-G0. The highest adsorption is achieved at pH 4.0 for both ester- and amino-terminated materials. Adsorption kinetic indicates the adsorption equilibrium can be reached at about 240 and 180 min for amino- and ester-terminated hybrids, respectively. Adsorption kinetic can be well fitted by pseudo-second-order kinetic model with film diffusion process as the rate-limiting step. Adsorption isotherm follows Langmuir model with monolayer adsorption behavior. Fourier transform infrared spectra (FTIR) indicate the adsorption of Cr(III) by PAMAM dendrimer mainly involve the participation of N–H and C=O groups. DFT calculation demonstrates the uptake of Cr(III) by ester-terminated adsorbents mainly involves carbonyl oxygen and secondary amine nitrogen atoms to form tetra-coordinated chelate, while that of amino-terminated one tends to form hexa-coordinated chelates by carbonyl oxygen, primary and secondary amine nitrogen atoms.

The damages of Mariana’s mining mud in the physiology of the brown algae Sargassum cymosum and its main epiphytic, the red algae Hypnea pseudomusciformis, were evaluated by controlled essays. Seaweeds were exposed to presence or absence of mud, isolated or in biological association, for 5 and 15 days. Measured parameters were growth rates, biochemical descriptors, and the chemical investigation of concentration and metal profile of the mud dissolved in seawater. Results showed that the highest values for metals were Al > Fe > Mn > Zn in both exposure periods. The mud also affected the growth rate with lethality in both isolated and associative treatments with H. pseudomusciformis after 15 days. According to our redundancy analysis (RDA), the profile and concentration of all metallic elements can induce different physiological responses of the organisms. We were able to observe a higher physiological adaptive ability of S. cymosum against the long-term presence of metals by the synthesis of phenolic compounds, while the deviation of metabolic routes in H. pseudomusciformis can be addressed as the main responsible for its lethality. Moreover, the presence of Hypnea in associative treatments reduces Sargassum’s detoxification ability. The present results reinforce the importance of biological interaction studies in a context of physiological resilience against mining mud pollution and mutual influences of species over the individual ability to avoid oxidative stress.

China’s Loess Plateau region has a weak ecological environment, and the government has invested a considerable amount of money to repair the ecological environment. Vegetation plays an important role in the ecological environment. The Sen slope analysis and the Mann-Kendall trend test were used to analyze the trend and significance of vegetation coverage from 2000 to 2015. The vegetation coverage was analyzed to investigate the influence of land use types and conversion. The Pearson Correlation Test and qualitative analysis were utilized at the pixel and regional scales to investigate the influence of meteorological factors and topographical factors. The fluctuation of vegetation in Shaanxi was analyzed from 2000 to 2015. The impact of anthropogenic activities was investigated using residual trend analysis. Hurst exponent and H/S analysis were applied to investigate the potential future vegetation coverage trend. The vegetation coverage in Shaanxi Province improved from 2000 to 2015. In unchanged land use types, all types showed significant improvements expect for other construction land. In changed land use types, most of the land use types converted into urban land showed degradation. All the land use types converted into dry land, forest, and unused land showed improvements. Ecological protection has achieved great results. Precipitation and temperature partly affect vegetation coverage in Shaanxi. Gradients and elevation affected the distribution of vegetation coverage and human activities influenced land use type and the ecological environment. In the future, potential degradation risks still exist in the parts of Shaanxi Province.

A common approach for waste management is their disposal in landfills, which is usually associated with the production of dangerous gases and of liquid leachate. Due to its toxicity, polluted liquid negatively impacts on the environment with the possible contamination of large volumes of soil, groundwater, and surface water. Leachate remediation is therefore subject of intensive research, and phytoremediation has been achieving increasing interest in recent decades. We describe here the suitability of vetiver grass for the remediation of two leachates collected in urban landfills of northern Italy, characterized by different composition. Our objective was measuring the accumulation/tolerance potential of this species and the evapotranspiration ability in a pot experiment, to evaluate applicability of vetiver plants for the reduction and decontamination of landfill leachate. Plants were grown for 4 months in pots with a zeolite growth bed and watered with either tap water (control) or undiluted landfill leachate. Plant growth and fitness and elemental content in shoots and roots were evaluated at the end of the experiment. In these experimental conditions, the high bioaccumulation of metals highlights the suitability of this species for its employment in phytoremediation; however, vetiver growth under leachate treatment was strongly dependent on leachate composition, making a case-to-case evaluation of plant tolerance necessary before large-scale application.

Visible light–responsive Pt-loaded coral-like BiFeO₃ (Pt-BFO) nanocomposite at different Pt loadings was synthesized via a two-step hydrothermal synthesis method. The as-synthesized photocatalyst was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectroscopy (UV–vis DRS), photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and magnetic hysteresis loop (M-H loop) analyses. The FESEM images revealed that Pt nanoparticles were evenly distributed on the coral-like BFO. The UV–vis DRS results indicated that the addition of Pt dopant modified the optical properties of the BFO. The as-synthesized Pt-BFO nanocomposite was effectively applied for the photodegradation of malachite green (MG) dye under visible light irradiation. Specifically, 0.5 wt% Pt-BFO nanocomposite presented boosted photocatalytic performance than those of the pure BFO and commercial TiO₂. Such a remarkably improved photoactivity could be mainly attributed to the formation of good interface between Pt and BFO, which not only boosted the separation efficiency of charge carriers but also possessed great redox ability for significant photocatalytic reaction. Moreover, the strong magnetic property of the Pt-BFO nanocomposite was helpful in the particle separation along with its great recyclability. The radical scavenger test indicated that hole (h⁺), hydroxyl (·OH) radical, and hydrogen peroxide (H₂O₂) were the main oxidative species for the Pt-BFO photodegradation of MG. Finally, the Pt-BFO nanocomposite was revealed high antibacterial activity towards Bacillus cereus (B. cereus) and Escherichia coli (E. coli) microorganisms, highlighting its potential photocatalytic and antibacterial properties at different industrial and biomedical applications.

High rates of irreversible oligo- or azoospermia are found among Nigerian men, leading many to consume herbal male sex enhancement products. The possibility of reproductive toxicity due to heavy metal contamination (Cr, As, Co, Hg, Cd, and Pb) of herbal products commonly used to boost libido or treat erectile dysfunction necessitated this study. In this study, herbal sex enhancement supplements were bought from pharmaceutical shops in Port Harcourt, Nigeria, and analyzed for heavy metals (Cr, As, Co, Hg, Cd, and Pb) contents using atomic absorption spectroscopy. The estimated daily metal intake (EDImetal), target hazard quotients (THQ), and total target hazard quotients (TTHQ) were determined. All the herbal sex enhancers used in this study contained heavy metals in these ranges: lead (0.032–0593), cobalt (0.025–0.075), cadmium (0.0011–0.048), and chromium (0.016–0.49) mg/kg. About 24.32% of the samples had TTHQ greater than 1. The EDImetal, THQ, and TTHQ of herbal sex enhancement supplements suggest that the use of some of these herbal sex enhancement supplements may not be risk-free after chronic exposure. Herbal sex enhancement supplements sold in Nigeria contain high levels of lead and cadmium. Since these metals are known to have male reproductive toxicity, these supplements may be adding to both the body burden of these metals and also implicated in the increasing incidence of male infertility in Nigeria.

In this study, we proposed integrated tools to evaluate the wind power potential, economic viability, and prioritize 15 proposed sites for the installation of wind farms. Initially, we used modified Weibull distribution model coupled with power law to assess the wind power potential. Secondly, we employed value cost method to estimate per unit cost ($/kWh) of proposed sites. Lastly, we used Fuzzy Technique for Order of Preference by Similarity to Ideal Solution (F-TOPSIS) to rank the best alternatives. The results indicate that Pakistan has enormous wind power potential that cost varies from 0.06 $/kWh to 0.58 $/kWh; thus, sites S12, S13, S14, and S15 are considered as the most economic viable locations for the installation of wind power project, while remaining sites are considered to be less important, due to other complexities. The further analysis using Fuzzy-TOPSIS method reveals that site S13 is the most optimal location followed by S12, S14, and S14 for the development of wind power project. We proposed that government should formulate wind power policy for the implementation of wind power projects in order to meet energy demand of the country.

The aim of the present work was to assess the efficiency of biochars obtained from the co-gasification of blends of rice husk + corn cob (biochar 50CC) and rice husk + eucalyptus stumps (biochar 50ES), as potential renewable low-cost adsorbents for Cr(III) recovery from wastewaters. The two gasification biochars presented a weak porous structure (ABET = 63–144 m² g⁻¹), but a strong alkaline character, promoted by a high content of mineral matter (59.8% w/w of ashes for 50CC biochar and 81.9% w/w for 50ES biochar). The biochars were used for Cr(III) recovery from synthetic solutions by varying the initial pH value (3, 4, and 5), liquid/solid (L/S) ratio (100–500 mL g⁻¹), contact time (1–120 h), and initial Cr(III) concentration (10–150 mg L⁻¹). High Cr(III) removal percentages (around 100%) were obtained for both biochars, due to Cr precipitation, at low L/S ratios (100 and 200 mL g⁻¹), for the initial pH 5 and initial Cr concentration of 50 mg L⁻¹. Under the experimental conditions in which other removal mechanisms rather than precipitation occurred, a higher removal percentage (49.9%) and the highest uptake capacity (6.87 mg g⁻¹) were registered for 50CC biochar. In the equilibrium, 50ES biochar presented a Cr(III) removal percentage of 27% with a maximum uptake capacity of 2.58 mg g⁻¹. The better performance on Cr(III) recovery for the biochar 50CC was attributed to its better textural properties, as well as its higher cation exchange capacity.

Monolithic algal green powder (MAGP) was fabricated based on the marine green macroalga Enteromorpha flexuosa. It was scrutinized by using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared (FT-IR), point of zero charge (PHPZC), and Brunauer–Emmett–Teller (BET) surface area. The ability of Enteromorpha flexuosa to capture both crystal violet (CV) and methylene blue (MB) from aqueous solutions was evaluated. The influence of variable conditional parameters on CV dye and MB dye batch sorption was investigated. Results showed that percentage removal of 90.3% and 93.4% were obtained under optimum conditions of variables for CV and MB, respectively. Effect of microwave radiation on dye sorption was also appraised. Processing the sorption under microwave irradiation (microwave-enforced sorption, MES) increases mass transfer and a contact time as low as 1 min is sufficient under optimized conditions (exposure time and power) reaching the equilibrium. The reusability of MAGP sorbent was achieved for four cycles of sorption/desorption by using 0.5 M HCl. The ability of MAGP for cationic dyes removal from spiked tap water and petrochemical plant discharge wastewater samples was successfully registered. Ultimately, the displayed data showed a superior and excellent ability of algal powder to be exploited as a green, harmless, and effective sorbent for cationic dye removal.

Widespread contamination of agricultural soil with Cd and As has resulted in substantial transfer and accumulation of these toxicants in rice grains. In the present study, we investigated the effects of chicken manure application on Cd and As concentrations and As speciation in the rice grains grown under different water conditions by pot experiment. Under aerobic condition, the application of chicken manure increased soil pH and soil Eh during most of the growth period of rice. Consequently, the application of chicken manure has little effect on total Cd, slightly decreased total As and inorganic As of rice grains when applied at rate of 2.0%. Under intermittent irrigation condition, the application of chicken manure increased soil pH and decreased soil Eh during most of the growth period of rice. Thus, chicken manure decreased total Cd, As, and inorganic As of rice grains. Besides, there was increased reduction of Cd and As with increase in the amount of chicken manure applied. Under flooded condition, the application of chicken manure increased soil pH before heading but decreased soil pH after heading. The application of chicken manure dramatically decreased total and inorganic As in rice grains, and slightly decreased Cd of rice grains. There was increased reduction of total As concentration with the increase in the amount of chicken manure applied. Meanwhile, the inorganic As concentration was the lowest when the concentration of chicken manure was 1.0%.