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排序方式: 共有588条查询结果,搜索用时 31 毫秒
1.
Prashant Mishra Kaman Singh Utkarsh Dixit Ankita Agarwal Rayees Ahmad Bhat 《印度化学会志》2022,99(7):100528
The threat of phenol contamination in aquatic ecosystems is significant for the health of the earth's water systems as well as all humans on it. The present study was conducted to synthesize a cost-effective adsorbent (pea shells activated with sulfuric acid, PSASA) from agriculture waste (pea shells) and its use for effective removal of toxic 4-Aminophenol (4-AP). Newly designed PSASA exhibited significant adsorption of 4-AP which was confirmed by SEM, FT-IR, and XRD analysis. Surface topography confirmed high unevenness of the PSASA surface and the macroporous feature of the PSASA was confirmed by BET analysis. . Multiple testing was done to see how various factors affected adsorption such as adsorbent dose, temperature, pH, PZC, the effect of KCl and urea addition and the effect of the initial concentration of 4-AP. A drop in adsorption uptake of 4-AP was observed as the temperature increases from 25 °C to 45 °C. Maximum adsorption uptake (qm) was found to be 106.11 mg/g at an optimum pH of 7.0 and 25 °C. Among various adsorption isotherm models tested, Langmuir Isotherm gave the best explanation with high R2 values of experimental data. The pseudo-first-order model was found to explain the kinetics of adsorption well. The thermodynamic finding confirms the adsorption process was physical and exothermic. The adsorption of 4-AP was primarily governed by electrostatic interaction, hydrogen-bonding and π-π exchange mechanism. Because of the positive outcomes of the present research, we can use the PSASA as a cost-effective adsorbent for removing phenolic compounds. 相似文献
2.
《Arabian Journal of Chemistry》2023,16(2):104517
The developing countries are suffering from the toxicity of different industrial effluents, especially dyes that contaminate water systems. This study successfully explained the preparation and characterization of nano bentonite to extract Direct Yellow Fifty (DY50). Direct Yellow 50 is an organic contaminant that may affect the quality of water. The characterization of prepared nanoparticles was done using Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR). The impact of different operating conditions was studied using different pH, dose, temperature, contact time, and initial DY50 concentrations. The obtained results indicated that nano bentonite could adsorb about 94 % at initial concentrations of 40 mg/L, respectively. The optimum removal conditions were observed at an acidic pH (pH 3) using a sorbent material dosage of 0.05 g for 4 h at 30 °C. The adsorption isotherm, kinetic analysis, and thermodynamic behavior were studied using linear equation form, and the adjusted R2 was compared to detect the preferred models. The adsorption behavior pseudo-second order kinetics, and fitted Langmuir isotherm model, respectively, showed the chemisorption interactions between adsorbed and sorbed molecules. Thermodynamic behavior indicated that the reaction was exothermic. Finally, this study strongly recommended using nano bentonite for DY50 removal from an aqueous solution. 相似文献
3.
《Arabian Journal of Chemistry》2022,15(1):103468
Removal of a troublesome textile dye, Direct Blue 71 (DB71) from water by a food waste compost was assessed in the current study. Since compost dye sorption is a multi-factor process influenced by mass, pH, concentration, temperature, contact time, and salinity, the cumulative influence of all parameters on DB71 removal was examined following an optimal multilevel multifactor experimental design. The process had to be presented using both linear and interaction terms, according to the variables analysis: Dye sorption = –0.050Mass + 0.122Conc–0.114pH + 0.132Time – 0.074Temp + 0.056Sal + 0.103Mass × Conc + 0.226 Mass × pH – 0.257Mass × Time – 0.112Mass × Temp – 0.041Mass × Sal + 0.008Conc × pH + 0.100Conc × Time + 0.089Conc × Temp + 0.167Conc × Sal – 0.245pH × Time – 0.231pH × Temp – 0.123pH × Sal + 0.358Tim × Temp + 0.355Tim × Sal – 0.045Temp × Sal (R2 = 0.9241)Salinity and pH were positively correlated with concentration, and contact time with temperature and salinity, to get better dye uptake. The optimal conditions for dye removal were the following: solid:liquid ratio 1:375, pH 3.0, initial dye concentration 400 mg L?1, contact time 240 min, salinity 0.6 M NaCl, temperature 50 °C. At the optimum combination of factors, equilibrium sorption isotherm and sorption kinetics were studied. Kinetic analysis indicated high sorption rate 4.0 mg g?1 min?1 while 28% of maximum capacity was reached within the first 10 min of interaction. Sorption isotherm has L2-shape which reflected surface saturation at high solute concentration with low competition with solvent molecules, with a maximum sorption capacity of 95.4 mg g?1. In column experiments performed at bed depth 5.1–12.8 cm, flow rate 1.0–2.0 mL min?1 and influent concentration 10–20 mg L?1, sorption capacity was 19.6 mg g?1, which represents 21% of the maximum capacity at equilibrium conditions. IR analysis of dye-loaded-compost confirmed the contribution of hydrophobic-hydrophobic forces in the sorption process. 相似文献
4.
《Arabian Journal of Chemistry》2022,15(11):104171
The effectiveness of Congo red (CR) adsorption from aqueous solutions onto MgAl-layered double hydroxide (MgAl-LDH) nanosorbents was examined in this study. MgAl-LDH was synthesized using the hydrothermal method, and physicochemical characterization was performed via powdered X-ray diffraction, high-resolution transmission electron microscopy, Fourier transform infrared analysis, and zeta potential measurements. For optimum adsorption of CR onto the synthesized MgAl-LDH nanosorbent, the adsorption process was employed in batch experiments. Adsorption parameters, such as the adsorbent dosage, solution pH, contact time, and initial adsorbate concentration, vary with the adsorption kinetics and isotherm mechanism. The results of the batch experiments indicated rapid adsorption of CR dye from aqueous solutions onto MgAl-LDH during the first 30 min until equilibrium was achieved at 180 min with a dye concentration of 50 mg/100 mL and MgAl-LDH adsorbent dosage of 0.05 g. The experimental adsorption data fit adequately with the monolayer coverage under the Langmuir isotherm model (R2 = 0.9792), and showed the best fit with the pseudo-second-order kinetic model (R2 = 0.996). The change in zeta potential confirmed the effective adsorption interaction between the positively charged MgAl-LDH and the negatively charged CR molecules with electrostatic interactions. This work is distinguished by the successful hydrothermal preparation of MgAl-LDH in the form of homogenous nanoscale particles (~100 nm). The prepared MgAl-LDH showed a high adsorption capacity toward anionic CR dye with a maximum adsorption capacity of 769.23 mg/g. This capacity is higher than those reported for other adsorbents in previous research. 相似文献
5.
利用磷酸活化法制备油茶果壳活性炭,并将其作为吸附剂用于去除水溶液中的Cr(Ⅵ),同时探讨了不同参数(Cr(Ⅵ)的初始浓度、吸附剂的用量、pH、温度等)对油茶果壳活性炭吸附Cr(Ⅵ)的影响。结果表明:当温度为293 K,Cr(Ⅵ)初始浓度为250 mg/L,pH为2.0时,Cr(Ⅵ)的最大吸附量可达165.0 mg/L。根据吸附动力学原理,发现其吸附过程遵循拟二级动力学模型。Cr(Ⅵ)的去除程度随Cr(Ⅵ)初始浓度的升高而增加,且其平衡数据与Freundlich模型拟合良好。 相似文献
6.
Brahim ABBOU Imane LEBKIRI Hanae OUADDARI Lamya KADIRI Abdelkarim OUASS Amar HABSAOUI Ahmed LEBKIRI El Housseine RIFI 《Turkish Journal of Chemistry》2021,45(2):362
In this work, we study the elimination of three bivalent metal ions (Cd2+, Cu2+, and Pb2+) by adsorption onto natural illitic clay (AM) collected from Marrakech region in Morocco. The characterization of the adsorbent was carried out by X-ray fluorescence, Fourier transform infrared spectroscopy and X-ray diffraction. The influence of physicochemical parameters on the clay adsorption capacity for ions Cd2+, Cu2+, and Pb2+, namely the adsorbent dose, the contact time, the initial pH imposed on the aqueous solution, the initial concentration of the metal solution and the temperature, was studied. The adsorption process is evaluated by different kinetic models such as the pseudo-first-order, pseudo-second-order, and Elovich. The adsorption mechanism was determined by the use of adsorption isotherms such as Langmuir, Freundlich, and Temkin models. Experiments have shown that heavy metals adsorption kinetics onto clay follows the same order, the pseudo-second order. The isotherms of adsorption of metal cations by AM clay are satisfactorily described by the Langmuir model and the maximum adsorption capacities obtained from the natural clay, using the Langmuir isotherm model equation, are 5.25, 13.41, and 15.90 mg/g, respectively for Cd(II), Cu(II), and Pb(II) ions. Adsorption of heavy metals on clay is a spontaneous and endothermic process characterized by a disorder of the medium. The values of ΔH are greater than 40 kJ/mol, which means that the interactions between clay and heavy metals are chemical in nature. 相似文献
7.
《Electroanalysis》2017,29(9):2019-2026
Nanostructured platinum‐iridium alloy microelectrode with high surface area was successfully prepared by applying successive potential cycles to a conventional PtIr microdisc in ionic liquid electrolyte containing ZnCl2 at elevated temperature. Scanning‐electron microscope studies show that a very thin nanostructured film was created on the electrode upon 20 potential cycles between −2.0 and 0.75 V versus a Ag pseudo‐reference electrode. The film nanostructures are characteristic of regular hill‐like nano‐spacings separated by valley‐like nano‐cracks, and a roughness factor of approximately 40. The nanostructured electrode is highly active towards electrochemical oxidation of ammonia, and generates a linear relation between voltammetric peak currents (or chronoamperometric currents), and logarithm of ammonia concentration in a range of approximately 1 ppm to 10000 ppm. It has been proposed that the Temkin adsorption of ammonia from the bulk solution onto the electrode surfaces was involved in its electrochemical oxidation and could be responsible for the linear current‐logarithmic concentration relation. 相似文献
8.
Present communication reports the preparation of Langmuir monolayer of water-soluble anionic dye Congo red (CR) by allowing it to adsorb from the aqueous subphase onto the preformed Langmuir monolayer of anionic stearic acid using divalent metal cations Mg2+ as mediator. Isotherm and compressibility studies of SA-Mg-CR hybrid monolayer gave valuable information about the molecular organisation in the Langmuir monolayer. Absorption spectroscopic studies revealed the formation of H-aggregates in the hybrid Langmuir–Blodgett (LB) films fabricated at lower salt concentration in the subphase. Atomic Force Microscopic image gave visual evidence of distinct nanocrystalline domains in the LB monolayer film. 相似文献
9.
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