Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH > ACPAH > ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution.     

Building Capacity for Protected Area Management in Lao PDR

Declining biodiversity in protected areas in Laos is attributed to unsustainable exploitation of natural resources. At a basic level, an important need is to develop capacity in academic and professional training institutions to provide relevant training to conservation professionals. The paper (a) describes the capacity building approach undertaken to achieve this goal, (b) evaluates the effectiveness of the approach in building capacity for implementing conservation and (c) reviews implementation outcomes. Strong linkages between organizations implementing field conservation, professional training institutions, and relevant Government agencies are central to enhancing effectiveness of capacity building initiatives aimed at improving the practice of conservation. Protected area management technical capacity needs will need to directly influence curriculum design to insure both relevance and effectiveness of training in improving protected area management. Sustainability of capacity building initiatives is largely dependent on the level of interest and commitment by host-country institutions within a supportive Government policy framework in addition to engagement of organizations implementing conservation.     

Enhanced solar-light-driven photocatalytic properties of novel Z-scheme binary BiPO4 nanorods anchored onto NiFe2O4 nanoplates: Efficient removal of toxic organic pollutants

Global environmental problems have been increasing with the growth of the world economy and have become a crucial issue. To replace fossil fuels, sustainable and eco-friendly catalysts are required for the removal of organic pollutants. In this study, nickel ferrite (NiFe₂O₄) was prepared using a simple wet-chemical synthesis, followed by calcination; bismuth phosphate (BiPO₄) was also prepared using a hydrothermal method. Further, NiFe₂O₄/BiPO₄ nanocomposites were prepared using a hydrothermal technique. Numerous characterization studies, such as structural, morphology, surface area, optical, photoluminescence, and photoelectrochemical investigations, were used to analyze NiFe₂O₄/BiPO₄ nanocomposites. The morphology analysis indicated a successful decoration of BiPO₄ nanorods on the surface of NiFe₂O₄ nanoplate. Further, the bandgap of the NiFe₂O₄/BiPO₄ nanocomposites was modified owing to the formation of a heterostructure. The as-prepared NiFe₂O₄/BiPO₄ nanocomposite exhibited promising properties to be used as a novel heterostructure for tetracycline (TC) and Rhodamine B (RhB) removal. The NiFe₂O₄/BiPO₄ nanocomposite degrades TC (98%) and RhB (99%) pollutants upon solar-light irradiation within 100 and 60 min, respectively. Moreover, the trapping experiments confirmed the Z-scheme approach of the prepared nanocomposites. The efficient separation and transfer of photogenerated electron-hole pairs rendered by the heterostructure were confirmed by utilizing electrochemical impedance spectroscopy, photocurrent experiments, and photoluminescence. Mott–Schottky measurements were used determine the positions of the conduction and valence bands of the samples, and the detailed mechanism of photocatalytic degradation of toxic pollutants was projected and discussed.     

Hunting for a Living: Wildlife Trade,Rural Livelihoods and Declining Wildlife in the Hkakaborazi National Park,North Myanmar

Hunting is a threat to wildlife within the Hkakaborazi National Park in north Myanmar. We used questionnaire surveys to obtain data on variables such as commonly targeted species, prices of traded wildlife, reasons for hunting and the relative importance of livelihood sources. We examine (a) the significance of hunting and trade for livelihoods and explore (b) the impacts of hunting on targeted species. Ninety per cent of trade records (n = 803) was constituted by seven species commonly targeted by hunters (serow, red goral, muntjac, bear, Assamese macaque, black musk deer and takin). Commercially valuable species previously targeted by hunters (tiger, otter, pangolin) appear to be completely absent from current harvest records and potentially in decline. Although farming is the predominant occupation, hunting (driven by trade) represents a significantly higher source of income than other livelihood activities. Management recommendations include increased investment in enforcement, education and outreach, small livestock development, improved crop productivity, demarcation of no-take areas for wildlife and biological monitoring of targeted species.     

Comparative toxicity study of a novel non-ionic surfactant, vanillin ethoxylates, and nonylphenol ethoxylates in Chinese hamster ovary cells in vitro

Surfactants such as alkylphenol polyethoxylates (APEOs) and nonylphenol ethoxylates (NPEOs) are commonly used worldwide, but the majority of these compounds, together with their metabolites, have been reported to induce severe biological toxicity. Here, we evaluated for the first time the cytotoxicity, genotoxicity and mitochondrial damage in Chinese hamster ovary (CHO-K1) cells caused by a novel non-ionic surfactant, vanillin ethoxylates (VAEOs), an alternative to APEOs. In parallel, the same in vitro bioassays were conducted on NPEOs along with their metabolic byproducts 4-nonylphenol (4-NP) and vanillin. The results showed that the cytotoxic potency order was NPEOs?>?4-NP?>?VAEOs > vanillin using CCK-8 assays. Also, 4-NP showed potential direct DNA damage in SOS/umu tests, whereas NPEOs, VAEOs and vanillin showed no positive result with and without S9 addition. In addition, none of the test compounds showed obvious genotoxic effects with low olive tail moment value using comet assays. However, all test compounds were shown to cause mitochondrial impairment by increasing mitochondrial mass and decreasing mitochondrial membrane potential in a concentration-dependent manner. And further analysis of reactive oxygen species (ROS) and mitochondrial superoxide (MNSOD) measurement showed that mitochondrial impairment was induced by oxidative stress with intracellular ROS and MNSOD overproduction. It's worth noting that VAEOs and vanillin cause relative lower cytotoxic, genotoxic and mitochondrial damage effects than NPEOs and 4-NP, indicating that VAEOs have the potential to substitute NPEOs as suitable surfactants. Take together, this study elucidates the toxicity profiles of VAEOs and NPEOs relatively comprehensively, and further toxicity analyses are suggested in the population, community and ecosystem.     

Effect of particulate matters on inactivation of bacteriophage MS2 under irradiation above 320 nm

Environmental Science and Pollution Research - The inactivation of bacteriophage MS2 under irradiation above 320 nm was investigated, focusing on different solution pH, ionic strength, and...     

Treatment of simulated Reactive Yellow 22 (azo) dye effluents using Spirogyra species

The potential of commonly available green algae belonging to Spirogyra species was investigated as viable biomaterials for biological treatment of simulated synthetic azo dye (Reactive Yellow 22) effluents. The results obtained from the batch experiments revealed the ability of the algal species in removing the dye colour and was dependent both on the dye concentration and algal biomass. Maximum dye colour removal was observed on the third day for all the system conditions. Monitoring of ORP values helped to understand the overlying biochemical mechanism of algal-dye system. Based upon the results, the dye-algal treatment mechanism was attributed to biosorption (sorption of dye molecules over the surface of algal cells), bioconversion (diffusion of dye molecules into the algal cells and subsequent conversion) and biocoagulation (coagulation of dye molecules present in the aqueous phase onto the biopolymers released as metabolic intermediates during metabolic conversion of dye and subsequent settlement).     

Sources and risk assessment of metal contamination in soils at the international airport of Shanghai,China

Concentrations of Cd, Pb, Zn, Cr, Cu, and Ni in soils at the Pudong International Airport (PIA) of Shanghai, China, were determined to assess the sources and potential ecological risks. Compared to the soil background values of Shanghai, 31 soil samples out of 33 were highly contaminated with Cd, and 76% were moderately contaminated by Cr, Ni, Pb, and Zn. Principal component analysis and clustering analysis indicated that Pb and Cd mainly originated from anthropogenic sources, while Zn, Cr, Ni, and Cu were mainly from natural sources. Relatively high concentrations of Cd and Pb were observed at sampling points near the landing or take-off sites or a close-by highway. Both air and highway traffic affected the quality of the soils at PIA.     

A Novel Biodegradable Green Poly(l-Aspartic Acid-Citric Acid) Copolymer for Antimicrobial Applications

Poly (l-aspartic acid-citric acid) green copolymers were developed using thermal polymerization of aspartic acid (ASP) and citric acid (CA) followed by direct bulk melt condensation technique. Antibacterial properties of copolymer of aspartic acid based were investigated as a function of citric acid content. This study is focused on the microorganism inhibition performance of aspartic acid based copolymers. Results showed that inhibition properties increase with increasing citric acid content. Characterization of obtained copolymers was carried out with the help of infrared absorption spectra (FTIR), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). The antibacterial activity of copolymers against bacteria like E-coli, Bacillus and pseudomonas was investigated. The copolymers showed excellent antimicrobial activities against three types of microorganisms. Overall studies indicated that the above copolymers possess a broad wound dressing activity against above three types of bacteria and may be useful as antibacterial agents.