Synthesis of green nano sorbents for simultaneous preconcentration and recovery of heavy metals from water.

The wastewater containing Cd, Co, Fe, Cu, Cr, Mn, Ni and Pb ions are as trace metal pollutants. Water pollution caused by increment in industrialization and overpopulation reveals a major threat to human health. Adsorption is recognized as the effective and optimum method to remove water contaminations. The amorphous and porous form of silicon dioxide is silica gel widely used as an adsorbent. It can absorb moisture with traces of the target heavy metal ions. This research elaborates a simplistic, and reliable preconcentration column method highly developed for the determination of Cd2+, Fe3+, Co2+, Cr3+, Cu2+, Mn2+, Pb2+ and Ni2+ ions in model solutions and real water samples by flame atomic absorption spectrometry (FAAS). The proposed operation depends on the retention of the target ions from buffered model solutions on a silica gel filled up a column modified with vanadium(V) oxide sorbent followed by their desorption. SiO2/V2O5 is an efficient adsorbent due to its low cost, eco-friendly and high availability. The adsorbent morphological and interfacial physicochemical characterization was done using scanning electron microscopy, and Fourier transmission infrared spectroscopy, respectively. The 2.92 value achieved for the point of zero charges supports the experimentation for the heavy metal efficient adsorption. Quantitative recoveries were achieved at pH 10 with 50 mg of SiO2/V2O5 mass and adsorption capacity ranged from 28.96 µmol/g (Pb) to 214.86 µmol/g (Fe) with 1114.79 µmol/g in total. Simultaneous preconcentration effect was determined by the interference cations on the sorbent. The LOD varies from 8.42 to 50.56 µg/L and LOQ is achieved from 20.06 to 72.41 µg/L of 15 blank solutions. The developed preconcentration procedure was adequately implemented for the simultaneous analysis of eight metallic ions content in local river samples. The developed vanadium(V) oxide incorporated with silica gel is practicable as an economical and effective adsorbent to eliminate metallic ions from a liquid solution.

Thermodynamic valorisation of lignocellulosic biomass green sorbents for toxic pollutants removal.

Various toxic heavy metals have become hazardous to human health as well as the environment. This research has been focused on a biosorption/bioremoval process of chromium (III), copper (II) and lead (II) ions from an aqueous solution by utilizing lignocellulosic biomass of Citrus limon peel (CLP) powder. CLP powder biomass was selected based on dietary fibre components having greater potential to remove target heavy metal ions in order to purify wastewater by following the eco-friendly biosorption method. At optimum conditions, the observed maximum removal efficiency of 97.47, 87.13 and 95.71% for Cr, Cu and Pb ions, respectively, was observed. An investigation has been made as a work of pH, CLP amount and temperature. The presented bio-removal processes by prepared CLP biosorbent manifested as a temperature-independent. Langmuir isotherm model was found an excellent fit of the isotherm data for tested systems with the calculated biosorption capacities of 111.11 (Cr), 76.92 (Cu) and 100 (Pb) mg/g. The positive ΔH values for selected target heavy metal ions, except lead ions, confirmed that the reaction was spontaneous and endothermic. A cooperative mechanism of second-order and intraparticle diffusion models during the adsorption processes of all three target ions was established with a higher coefficient of determination and more closely anticipated take-up (adsorption capacity). Furthermore, the interaction of -OH and -COOH functional groups of CLP that have a major role in the removal of Cr, Cu and Pb ions from single-ion aqueous solution and/or a surface biosorption was confirmed based on the results presented by SEM-EDS and FTIR analysis. Analysis from XRD revealed peak corresponding to amorphous cellulose type I as observed by FT-IR analysis.

Heavy metals content in ashes of wood pellets and the health risk assessment related to their presence in the environment.

Efforts to reduce air pollution in developing countries may require increased use of biomass fuels. Even biomass fuels are a sustainable alternative to fossil fuels there is limited quantitative information concerning heavy metal content in their ashes. Therefore, this study focuses on the determination of the heavy metal concentrations in wood pellet ash obtained from the combustion of 10 pellet brans from Bosnia and Herzegovina and Italy, the effects of adding the ashes to soils, and the assessment of health risk assessment. Ash content was determined by gravimetric method. The amount and composition of ash remaining after combustion of wood pellets varies considerably according to the type of biomass and wood from which the pellet is made. Samples were prepared by wet digestion using HNO3, and heavy metals are determined by atomic absorption spectroscopy-flame and graphite furnace. The results showed that the lowest concentration in ashes was obtained for Co 0.01 mg kg-1 and the highest for Fe 571.63 mg kg-1. The Hazard Index (HI), calculated for non-cancerous substances for children was 2.23E-01, and the total Risk index was 4.54E-05. As for adults, HI was 1.51E-02, while the Risk index value was 3.21E-06. Human health risk calculated through HI and Risk index for children and adults associated with analyzed pellets is not of significant concern. The calculated enrichment factor and metal pollution index for wood pellet ashes indicate the risk of soil contamination with heavy metals. From this point of view, analyzed samples of ashes could be a serious contaminant of soil, so further monitoring is required.

Lead Exposure Influences Serum Biomarkers, Hepatocyte Survival, Bone Marrow Hematopoiesis, and the Reproductive Cycle in Japanese Quails.

Lead toxicity has been a hallmark issue of toxicology over the last decades. However, predictive and non-robust models did not provide complete data on low-dose lead interaction with the organism at different functional levels (e.g., blood-serum-liver-bone marrow-bursa fabricii-reproductive system axis). Japanese quails are an animal model with a strong immune system, making them suitable for the thorough assessment of in vivo chronic lead toxicity. In this study, we have exposed Japanese quails via water ingestion to 0.25 and 0.5 µg/mL lead(II) chloride (PbCl2) for 20 days and assessed blood cells, serum biomarkers, hepatocyte survival, bone marrow hematopoiesis, bursa fabricii, and lead accumulation in eggs. Blood cells passed through morphological alterations (loss and inversion of the erythrocyte nucleus, multiple erythrocyte and thrombocyte aggregation, lymphocyte degradation, and blast cell infiltration). In the serum, PbCl2 increased the activity of creatine kinase (CK) and lactate dehydrogenase (LDH); increased the level of cholesterol, sodium, creatinine, and urea; and reduced the level of proteins, triglycerides, chloride, potassium, calcium, and alkaline phosphatase (ALP) activity (P < 0.05). Liver tissue of the exposed animals exhibited apparent death of hepatocytes. In the bone marrow, macrophages and heterophils contained a vast number of the infiltrated/uptaken granules upon PbCl2 exposure. Ultimately, PbCl2 exposure elicited a series of events observed first in the blood and serum parameters and later translated to the hematopoietic centers.

Amperometric determination of bonded glucose with an MnO(2) and glucose oxidase bulk-modified screen-printed electrode using flow-injection analysis.

A screen-printed amperometric biosensor based on carbon ink double bulk-modified with MnO(2) as a mediator and glucose oxidase as a biocomponent was investigated for its ability to serve as a detector for bonded glucose in different compounds, such as cellobiose, saccharose, (-)-4-nitrophenyl-beta-d-glucopyranoside, as well as in beer samples by flow-injection analysis (FIA). The biosensor could be operated under physiological conditions (0.1M phosphate buffer, pH 7.5) and exhibited good reproducibility and stability. Bonded glucose was released with glucosidase in solution, and the free glucose was detected with the modified screen-printed electrode (SPE). The release of glucose by the aid of glucosidase from cellobiose, saccharose and (-)-4-nitrophenyl-beta-d-glucopyranoside in solution showed that stoichiometric quantities of free glucose could be monitored in all three cases. The linear range of the amperometric response of the biosensor in the FIA-mode flow rate 0.2mLmin(-1), injection volume 0.25mL, operation potential 0.48V versus Ag/AgCl) extends from 11 to 13,900mumolL(-1) glucose in free form. The limit of detection (3sigma) is 1mumolL(-1) glucose. A concentration of 100mumolL(-1) yields a relative standard deviation of approximately 7% with five injections. These values correspond to the same concentrations of bonded glucose supposed that it is liberated quantitatively (incubation for 2h with glucosidase). Bonded glucose could be determined in beer samples using the same assay. The results corresponded very well with the reference procedure.