The adsorption of 63Ni from aqueous solutions using NKF-6 zeolite was investigated by a batch technique under ambient conditions. The adsorption was investigated as a function of contact time, pH, ionic strength, foreign ions, humic substances (FA/HA) and temperature. The kinetic adsorption was well described by the pseudo-second-order rate equation. The adsorption of 63Ni on NKF-6 zeolite was strongly dependent on pH and ionic strength, and the adsorption of 63Ni increased with increasing NKF-6 zeolite content. At low pH values, the presence of FA enhanced the adsorption of 63Ni on NKF-6 zeolite, but the presence of HA had no drastic effect. At high pH values, the presence of FA or HA decreased the adsorption of 63Ni on NKF-6 zeolite. The adsorption isotherms were well represented by the Langmuir model. The thermodynamic parameters (i.e., ΔH0, ΔS0and ΔG0) for the adsorption of 63Ni were determined from the temperature dependent isotherms at 293.15, 313.15 and 333.15 °K, respectively, and the results indicate that the adsorption reaction was favored at high temperature. The results suggest that the adsorption process of 63Ni on NKF-6 zeolite is spontaneous and endothermic. 相似文献
Sugarcane bagasse and hydroponic lettuce roots were used as biosorbents for Cu(II), Fe(II), Zn(II), and Mn(II) removal from monoelemental solutions in aqueous medium, at pH 5.5, using batch procedures. These biomasses were studied in natura (lettuce roots, NLR, and sugarcane bagasse, NSB) and modified with HNO3 (lettuce roots, MLR, and sugarcane bagasse, MSB). Langmuir, Freundlich, and Dubinin-Radushkevich non-linear isotherm models were used to evaluate the data from the metal ion adsorption assessment. The maximum adsorption capacities (qmax) in monoelemental solution, calculated using the Langmuir isothermal model for Cu(II), Fe(II), Zn(II), and Mn(II), were respectively 24.61, 2.64, 23.04, and 5.92 mg/g for NLR; 2.29, 16.89, 1.97, and 2.88 mg/g for MLR; 0.81, 0.06, 0.83, and 0.46 mg/g for NSB; and 1.35, 2.89, 20.76, and 1.56 mg/g for MSB. The Freundlich n parameter indicated that the adsorption process was favorable for Cu(II) uptake by NLR; Fe(II) retention by MLR and MSB; and Zn(II) sorption by NSB, MLR, and NSB and favorable for all biomasses in the accumulation of Mn(II). The Dubinin-Radushkevich isotherm was applied to estimate the energy (E) and type of adsorption process involved, which was found to be a physical one between analytes and adsorbents. Organic groups such as O–H, C–O–C, CH, and C=O were found in the characterization of the biomass by FTIR. In the determination of the biomass surface charges by using blue methylene and red amaranth dyes, there was a predominance of negative charges. 相似文献
Sugarcane bagasse and hydroponic lettuce roots were used as biosorbents for the removal of Cu(II), Fe(II), Mn(II), and Zn(II) from multielemental solutions and lake water, in batch processes. These biomasses were studied in natura (lettuce roots, NLR, and sugarcane bagasse, NSB) and chemically modified with HNO3 (lettuce roots, MLR, and sugarcane bagasse, MSB). The results showed higher adsorption efficiency for MSB and either NLR or MLR. The maximum adsorption capacities (qmax) in multielemental solution for Cu(II), Fe(II), Mn(II), and Zn(II) were 35.86, 31.42, 3.33, and 24.07 mg/g for NLR; 25.36, 27.95, 14.06, and 6.43 mg/g for MLR; 0.92, 3.94, 0.03, and 0.18 mg/g for NSB; and 54.11, 6.52, 16.7, and 1.26 mg/g for MSB, respectively. The kinetic studies with chemically modified biomasses indicated that sorption was achieved in the first 5 min and reached equilibrium around 30 min. Sorption of Cu(II), Fe(II), Mn(II), and Zn(II) in lake water by chemically modified biomasses was 24.31, 14.50, 8.03, and 8.21 mg/g by MLR, and 13.15, 10.50, 6.10, and 5.14 mg/g by MSB, respectively. These biosorbents are promising and low costs agricultural residues, and as for lettuce roots, these showed great potential even with no chemical modification. 相似文献
Environmental Science and Pollution Research - Fluoride, a geochemical element, can damage the brain and result in dysfunction of the central nervous system. In recent years, fluoride-induced... 相似文献
The interaction between green finance and other factors, such as ecological environment, has been a research hotspot nowadays. Especially, the reasonable guiding of capital into energy conservation and environmental protection industries would greatly affect those factors, so as to the relation between them. This paper aimed to analyze the relationships between green finance, technological progress, and ecological performance quantitatively. The entropy method was used to respectively construct the system of index for green finance and technological progress, and index for ecological performance was measured by the super-SBM model. The panel vector autoregressive (PVAR) model was selected to empirically analyze dynamic relationships based on datasets from 30 provinces in China during 2008–2019 period. The results told that (1) from 2008 to 2019, China’s overall level of green finance, technological progress and ecological performance increased to varying degrees. Spatially, the areas with high-developed green finance greatly coincided with those such as large cities or the eastern coast that had good financial development. The distribution of technological progress index were similar, except some underdeveloped areas with relatively advanced scientific research institutes. The ecological performance, however, was high in the South and low in the north. (2) In the lag for 3 years, the influence of green finance on ecological performance in different regions was all positive for that all the coefficient symbols that passed the significance test were above 0, while that on technological progress was negative first and then positive. And the effects of technological progress on ecological performance were positive in ecological regions and negative in low ecological regions (0.0893 and -0.1211 in the case of three-stage lag respectively). (3) The contribution of green finance to ecological performance was high according to the results of variance decomposition, maintained at about 30%, and that of technological progress increased year by year (from 0.000 to 0.039). Therefore, we proposed to strengthen the development of green finance in underdeveloped regions. The emphasis should be laid on the researches and applications of green technology, the formulation of financing policies in innovation compensation and the establishment of a dynamic monitoring system for the ecological environment.
Water pollution caused by the discharged insolubility petroleum contaminants and organic compound dyes seriously threatens the natural self-purity capacity of the water body and the survival of aquatic species, so it is imperative to restraint the deterioration of the aquatic environment. In this paper, pathways are propounded for the simultaneous removal of insoluble spilling oil and organic dye contaminants. Particularly, hydrophobic ZnSnO3 after stearic acid modification and Bi2MoO6 photocatalysts are introduced into the cotton fabric substrate through solution dip-coating. The durability of the prepared fabric suffers from the acid–base corrosion, thermal treatment and mechanical wear, while still exhibiting remarkable water-repellent (WCA?>?150°) property. Furthermore, the remarkable photocatalytic activity makes it possible for reusable degradation and the primary active species, namely the holes, to be verified by the radicals-capturing experiment. It is worth observing that as-prepared superhydrophobic fabric possesses admirable water-proof property and cycling durability of decomposing toxic water-soluble organic dye, thereby contributing to further realizing the ecological concept of clear waters.