Zobrazení zdroje stránky Celikhendricks1964

Low-cost adsorbent, pine bark biochar (PBB) from the forest residue, was produced and applied to remove tetracycline (TC) from aqueous solution via adsorption pathway. The PBB, hence obtained, was modified using aqueous ferric and ferrous ion solutions to obtain magnetic pine bark biochar (M-PBB). Batch adsorption experiments were conducted to examine the adsorption of TC by PBB and M-PBB in the variation of pH, contact time, dosage, and temperature. The adsorbents were characterized by SEM/EDX, TGA, and pHpzc. The adsorption mechanism was evaluated by fitting Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) isotherms model. Also, the experimental data were analyzed by kinetics models (pseudo-first-order, pseudo-second-order, intra-particle diffusion, and Elovich) and thermodynamics. The maximum adsorption capacity (qm) of M-PBB was 15.3 mg/g from the experiment at pH 6. A high correlation coefficient (R2 ≈ 0.9) of Freundlich isotherm postulated multi-layer adsorption of TC on M-PBB at pH 6. The kinetic studies showed that the pseudo-first-order was more suitable for representing the adsorption of TC molecules on the surface. The thermodynamic analysis was showed that the adsorption process is favorable, spontaneous, and endothermic at studied temperatures. M-PBB demonstrated a potential for removal of TC from water as a low-cost and convenient adsorbent.Diazotrophs carry out biological nitrogen (N) fixation process that replenishes available soil N; it is unclear how soil diazotrophic communities respond to biochar and chemical fertilizer amendment in agricultural ecosystem. Herein, we studied the impacts of biochar and chemical fertilizer amendment on diazotrophic communities in rhizosphere and bulk soils using nifH gene. The field experiment included four treatments control (CK), biochar (B), chemical NPK fertilizer (CF), and biochar + chemical fertilizer (B + CF). nifH gene abundance in rhizosphere soils ranged from 9.00 × 107 to 2.57 × 108 copies g-1 dry soil among the different treatments, which was 1.42-2.68 times higher compared with the bulk soils ranging from 5.83 × 107 to 1.19 × 108 copies g-1 dry soil. Single application of biochar increased the abundance of nifH gene, whereas chemical fertilizer addition significantly decreased it in the bulk and rhizosphere soils. Single biochar addition affected diazotrophic community composition in rhizosphere soil, but not in the bulk soil. However, both CF and B + CF treatments obviously changed the community structure of diazotrophs in both soils. Moreover, rhizosphere effect enhanced nifH gene abundance and significantly altered the diazotrophic community structure compared to bulk soil. Phylogenetic analysis showed that all nifH sequences were affiliated to the cyanobacteria, α-, β-, γ-, and δ- subclasses of the proteobacteria group. Soil nutrient availability rather than pH had significant impacts on diazotrophic community structure based on mantel test and redundancy analysis. Overall, biochar improves the diazotrophic abundance, while chemical fertilization negatively affects it by altering nutrient availability, and combined application of biochar and chemical fertilizer does not counteract the adverse influences of chemical fertilizer on nitrogen-fixing microorganisms.Research on phase change material (PCM) for thermal energy storage is playing a significant role in energy management industry. However, some hurdles during the storage of energy have been perceived such as less thermal conductivity, leakage of PCM during phase transition, flammability, and insufficient mechanical properties. For overcoming such obstacle, researchers have been concentrating on composite PCM, where PCM is combined with metal or non-metal particles, fibrous materials, expanded or porous materials, and flame retardants. The main purpose of the current paper is to review the properties enhanced paraffin-based composite PCM. In the literature review, paraffin is selected as a thermal energy storage material, which is mixed with property-enhancing material to prepare composite. Structural and thermal properties of composite have been explored with the help of scanning electron microscope, X-ray diffractometer, transmission electron microscope, polarizing optical microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. Mechanical properties of the material are also portrayed using different testing techniques. Nevertheless, numerical methods have also been adopted for characterization of composite. It is found from the literature review that with incorporation of property-enhancing material, thermal conductivity, phase transition rate, and shape stability of PCM increased at the same time flammability, heat storage capacity, and mechanical properties reduced.Achieving advanced treatment of phosphorus (P) to prevent water eutrophication and meet increasingly stringent wastewater discharge standard is an important goal of water management. In this study, a low-cost, high-efficiency phosphate adsorbent zirconium-modified biochar (ZrBC) was successfully synthesized through co-precipitation method, in which the biochar was prepared from the pyrolysis of peanut shell powder. ZrBC exhibited strong adsorption ability to low-concentration phosphate ( less then  1 mg·L-1) in water, and the phosphate removal reached 100% at the investigated dosage range (0.1-1.0 mg·L-1). The adsorption process could be described well by pseudo-second-order model and Langmuir isotherm model, indicating that the phosphate adsorption by ZrBC was mainly a chemical adsorption and single-layer adsorption process. The calculated static maximum phosphate adsorption capacity was 58.93 mg·g-1 at 25 °C. The ligand exchange between surface hydroxyl groups and phosphate was the main mechanism for the phosphate adsorption on ZrBC. The presence of coexisting anions except for SO42- had little effect on the phosphate removal. At the column experiment, ZrBC showed superior treatment capacities for simulated secondary effluents and the breakthrough time for 0.5 mg·L-1 effluent phosphate concentration reached 190 h. ZrBC highlights the potential as an effective and environment-friendly adsorbent for the removal of low-concentration phosphate from secondary effluents of municipal wastewater treatment plants (WWTPs).Since large areas of agricultural soils around the world are contaminated by Cd, a cost-effective and practical method is needed for the safe production of edible plants. The effective role of many nanomaterials to improve plant yield by mitigating environmental pollutions is addressed; however, the impacts of selenium nanoparticles (Se-NPs) have not been well-known yet. The aim of this work was to investigate foliar application of Se-NPs on yield, water content, proline concentration, phenolic content, lipid peroxidation, and essential oil (EO) attributes of coriander (Coriandrum sativum L.) under Cd stress. The plants were exposed to Cd contamination (0, 4, and 8 mg L-1) and foliar application of Se-NPs (0, 20, 40, and 60 mg L-1). The results showed increased Cd accumulation in roots and shoots of coriander plants upon Cd stress; however, Se-NPs alleviated the uptake of Cd. [https://www.selleckchem.com/products/nexturastat-a.html Nexturastat A ic50] Cd toxicity, particularly 8 mg L-1, decreased shoot and root weight, chlorophyll (Chl), and relative water content (RWC), while Se-NPs improved these attributes. The Cd concentration at 4 mg L-1 and Se-NPs at 40 or 60 mg L-1 increased phenolic and flavonoid contents as well as EO yield. Proline concentration and malondialdehyde (MDA) increased by enhancing Cd stress, but Se-NPs decreased MDA. The GC/MS analysis showed that the main EO constitutes were n-decanal (18.80-29.70%), 2E-dodecanal (14.23-19.87%), 2E-decanal (12.60-19.40%), and n-nonane (7.23-12.87%), representing different amounts under Cd pollution and Se-NPs. To sum up, Se-NPs at 40-60 mg L-1 are effective in alleviating Cd stress.Risk is associated with every sector of an economy, and the pervasiveness of risk in agriculture is not new to farmers; they have, over the decades, developed ways to minimize and cope with it. The question is whether traditional strategies employed by farmers are adequate to curb unavoidable natural disasters. This study aims to see how crop insurance affects cocoa producers' incomes in Ghana. A well-structured questionnaire was delivered to a sample of 600 cocoa farmers in Ghana's Ashanti region, and data was collected using a multi-stage random sampling technique. Tobit and propensity score matching effect estimators were used to examine crop insurance's impact on cocoa farmers' income. We found that the age of a cocoa farmer has a negative effect on the farmer's income and is statistically significant. Our result also shows that the marital status of cocoa farmers has a significant positive impact on their income. The relationship between savings and farmers' income was positive in our estimation. It indicates that an increase in savings attitude leads to a higher income for the farmers. The result indicates that crop insurance had a significant positive impact on cocoa farmers' income in the Ashanti region. The study recommends that the government of Ghana, with urgency, design agricultural insurance policy that can capture various farmers in the country to enhance their income and reduce poverty. Again, insurers need to promote publicity through public seminars, training, and media advertising to improve farmer awareness and knowledge of the insurance scheme.Mudflat sediment cores from lower (C-1), middle (C-2), and lower regions of upper (C-3) Chapora Estuary were investigated for grain size composition, total organic carbon, total and bioavailable Fe, Mn, Cu, Co, Ni, and Zn to assess metal contamination. Accumulation of metals by Saccostrea cucullata was studied to understand metal toxicity. In core C-1, Fe, Mn, Cu, Co, Ni, and Zn showed an average concentration of 1.73%, 648 ppm, 12 ppm, 12 ppm, 16 ppm, and 25 ppm, respectively, while core C-2 revealed their average concentration as 1.34%, 709 ppm, 10 ppm, 11 ppm, 13 ppm, and 28 ppm respectively. In core C-3, an average concentration of Fe, Mn, Cu, Co, Ni, and Zn was 1.72%, 907 ppm, 14 ppm, 13 ppm, 18 ppm, and 31 ppm respectively. Metals in sediments varied within the estuary due to hydrodynamics, discrepancies in metal sources and sand mining-induced remobilization of metals. Correlation and principal component analysis revealed Fe oxides as the key regulator of trace metal distribution in sediments along with clay and total organic carbon. Enrichment factor (EF) and geo-accumulation index (Igeo) showed more or less moderate contamination of Mn in core C-3. Also, the potential contamination index (PCI) indicated moderate contamination of Mn in core C-3 using the shale value as background concentration, whereas the application of upper crustal value revealed moderate contamination of Fe, Mn, Cu, Co, and Ni in core C-1, Mn, Co, and Ni in core C-2 and of Cu, Co, and Ni in core C-3. Mn was severely to very severely contaminated in core C-3. The mean probable effect level quotient and mean effect range median quotient showed medium to low-level contamination of Cu, Ni, and Zn. Metals were considerably allied to Fe-Mn oxide and organic/sulphide fractions which revealed their bioavailability. Mn was 36% in labile form (lower estuary) and indicated a high risk to biota. Mn, Ni, and Zn in Saccostrea cucullata exceeded the permissible limit and suggested toxicity and non-suitability for human consumption.