scholarly journals Adsorption and photocatalysis for methyl orange and Cd removal from wastewater using TiO 2 /sewage sludge-based activated carbon nanocomposites

2017 ◽  
Vol 4 (12) ◽  
pp. 170834 ◽  
Author(s):  
M. Nageeb Rashed ◽  
M. A. Eltaher ◽  
A. N. A. Abdou

Nanocomposite TiO 2 /ASS (TiO 2 nanoparticle coated sewage sludge-based activated carbon) was synthesized by the sol-gel method. The changes in surface properties of the TiO 2 /ASS nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence. The prepared TiO 2 /ASS nanocomposite was applied for simultaneous removal of methyl orange dye (MO) and Cd 2+ from bi-pollutant solution. The factors influencing photocatalysis (TiO 2  : ASS ratios, initial pollutant concentrations, solution pH, nanocomposite dosage and UV irradiation time) were investigated. The results revealed that high removal efficiency of methyl orange dye (MO) and Cd 2+ from bi-pollutant solution was achieved with TiO 2 /ASS at a ratio (1 : 2). The obtained results revealed that degradation of MO dye on the TiO 2 /ASS nanocomposite was facilitated by surface adsorption and photocatalytic processes. The coupled photocatalysis and adsorption shown by TiO 2 /ASS nanocomposite resulted in faster and higher degradation of MO as compared to MO removal by ASS adsorbent. The removal efficiency of MO by ASS adsorbent and TiO 2 /ASS (1 : 2) nanocomposite at optimum pH value 7 were 74.14 and 94.28%, respectively, while for Cd 2+ it was more than 90%. The experimental results fitted well with the second-order kinetic reaction.

2010 ◽  
Vol 152-153 ◽  
pp. 1322-1327 ◽  
Author(s):  
Cong Jin Chen ◽  
Long Bin Wei ◽  
Peng Cheng Zhao ◽  
Yue Li ◽  
Hua Yu Hu ◽  
...  

In this paper, the feasibility of preparing activated carbon from corncob furfural residue with ZnCl2 by microwave irradiation was studied. The effect of the ratio by weight of ZnCl2 to corncob furfural residue, ZnCl2 solution soaking time, microwave irradiation time and the pH value of ZnCl2 solution on the quality of activated carbon was investigated. On the condition that the microwave power is 800 W and ZnCl2 solution mass concentration is 50%, the best technological parameter on preparing activated carbon with ZnCl2 by microwave irradiation is obtained: at the ratio of 3.5:1 by weight of ZnCl2 to corncob furfural residue, microwave irradiation time is 20 min, ZnCl2 solution soaking time is 12 h, the pH value of ZnCl2 solution is 2, the activated carbon yield reached 33.1% and the decolorizing capacity for methylene blue is 202.5 mg/g, the product is used in treating Cr6+ solution(pH value 4.0, concentration 50 mg/L), its adsorption capacity of Cr6+ is 7.583 mg/g.


Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 824
Author(s):  
Li-Yuan Zhang ◽  
Jia You ◽  
Qian-Wen Li ◽  
Zhi-Hong Dong ◽  
Ya-Jie Zhong ◽  
...  

F–TiO2 was prepared by a simple precipitation method using titanium sulfate as the titanium source, hydrogen fluoride as the fluorine source and ammonia as the precipitant. CdS/F–TiO2 composites were prepared by hydrothermal synthesis of CdS and F–TiO2. The surface morphology, crystal phase composition, ultraviolet absorption band, fluorescence intensity, element composition, valence state, specific surface and pore structure of the samples were characterized by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), ultraviolet visible absorption spectrum (UV-Vis-Abs), Molecular fluorescence spectrophotometer (PL) and X-Ray photoelectron spectroscopy (XPS) and Surface area analyzer (BET), respectively. The effects of the dosage of the photocatalyst, pH value, the concentration of methyl orange and the addition of H2O2 on the photocatalytic performance were investigated with methyl orange solution as the target degradation product. The results showed the optimum condition for photodegradation of methyl orange by 1% CdS/F–TiO2 is that the pH value, the solid-liquid ratio, the concentration of methyl orange and the dosage of H2O2 is 2, 2 g/L, 10 mg/L and 3%, respectively. Under the same conditions, the degradation rate of methyl orange by 1% CdS/F–TiO2 was 93.36% when 300 W metal halide lamp was irradiated for 20 minutes, which was significantly higher than that of F–TiO2. CdS has a significant effect on the morphology, crystallinity, grain size and the compound probability of electrons and holes after the F–TiO2 modification. The composite causes a significant red shift at the edge of the F–TiO2 light absorption band. The photocatalytic degradation of methyl orange by 1% CdS/F–TiO2 follows the Langmuir-Hinshelwood first-order kinetic model.


2012 ◽  
Vol 610-613 ◽  
pp. 1639-1644
Author(s):  
Wei Fang Dong ◽  
Li Hua Zang ◽  
Qi Lei Feng

This study investigated the treatment of methyl orange dye from aqueous solution with granular activated carbon as sorbents. Adsorption experiments were carried out at different contact time, the dosage of granular activated carbon, pH and initial dye concentration.Orthogonal experiment was designed to analyze the influence degree of operating parameters for optimizing adsorption process. The results demonstrated that the dosage of granular activated carbon had the greatest impact on the removal efficiency of methyl orange , followed by pH, contact time and initial concentration of methyl orange . The granular activated carbon possessed good adsorption capacity to methyl orange which the removal efficiency could reached 98.06% at the optimum dosage 4g and optimum time 90min.


2017 ◽  
Vol 4 (1) ◽  
pp. 6021-6021
Author(s):  
Mohammad Reza Samarghandi ◽  
Ali Poormohammadi ◽  
Samane Shanesaz ◽  
Kazem Godini

The current study aimed at comparing the performances of activated carbon and graphene in the removal of reactive red 198. The experiments were conducted in a batch reactor and the effects of some operational parameters including initial dye concentration, pH, contact time, and different doses of activated carbon and graphene on the removal efficiency of dye were investigated. The results showed that the adsorption efficiency was affected by initial dye concentration. In general, with increasing contact time up to 180 minutes, the removal efficiency increased significantly. The removal efficiency of reactive red 198 increased with increasing contact time, and after 60 minutes of contact time, adsorption phase reached the equilibrium. When activated carbon was used, the maximum removal efficiency happened at pH 3. At this pH value, reactive red 198 was removed completely (100%) after 120 minutes, whereas the minimum efficiency was observed at pH 10. A similar trend was also observed for graphene as an adsorbent. Moreover, the removal efficiency of the dye by both adsorbents increased with the increase of the adsorbent dosage. The experimental data showed that the adsorption of reactive red198 on both active carbon and graphene fitted well into the second-order kinetic model. Active carbon and graphene fitted well Langmuir 1 model. According to the results, graphene acts as suitable adsorbent and can be applied in treating several industrial effluents and contaminated water in greater scales. The main upside of grapheme, in comparison with activated carbon, is that it reaches the equilibrium in a shorter time. Further, grapheme adsorbed the dye nearly completely (98% to 100%).


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4483
Author(s):  
Yuyingnan Liu ◽  
Xinrui Xu ◽  
Bin Qu ◽  
Xiaofeng Liu ◽  
Weiming Yi ◽  
...  

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.


2021 ◽  
Vol 13 (3) ◽  
pp. 371-380
Author(s):  
Yongjun Wu ◽  
Nina Xie ◽  
Lu Yu

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.


2019 ◽  
Vol 84 (7) ◽  
pp. 713-727 ◽  
Author(s):  
Jiteng Wan ◽  
Chunji Jin ◽  
Banghai Liu ◽  
Zonglian She ◽  
Mengchun Gao ◽  
...  

Even in a trace amounts, the presence of antibiotics in aqueous solution is getting more and more attention. Accordingly, appropriate technologies are needed to efficiently remove these compounds from aqueous environments. In this study, we have examined the electrochemical oxidation (EO) of sulfamethoxazole (SMX) on a Co modified PbO2 electrode. The process of EO of SMX in aqueous solution followed the pseudo-first-order kinetics, and the removal efficiency of SMX reached the maximum value of 95.1 % within 60 min. The effects of major factors on SMX oxidation kinetics were studied in detail by single-factor experiments, namely current density (1?20 mA cm-2), solution pH value (2?10), initial concentration of SMX (10?500 mg L-1) and concentration of electrolytes (0.05?0.4 mol L-1). An artificial neural network (ANN) model was used to simulate this EO process. Based on the obtained model, particle swarm optimization (PSO) was used to optimize the operating parameters. The maximum removal efficiency of SMX was obtained at the optimized conditions (e.g., current density of 12.37 mA cm-2, initial pH value of 4.78, initial SMX concentration of 74.45 mg L-1, electrolyte concentration of 0.24 mol L-1 and electrolysis time of 51.49 min). The validation results indicated that this method can ideally be used to optimize the related parameters and predict the anticipated results with acceptable accuracy.


2012 ◽  
Vol 518-523 ◽  
pp. 2099-2103
Author(s):  
Guang Zhou Qu ◽  
Hai Bing Ji ◽  
Ran Xiao ◽  
Dong Li Liang

The activated carbon fiber (ACF) was treated by different concentration nitric acid (HNO3) and hydrogen peroxide (H2O2) oxidization to enhance its adsorption capacity to hexavalent chromium (Cr6+) ion. The adsorption amount and adsorption kinetics of Cr6+ion on ACFs, and the surface chemical groups were investigated. The results showed that the modified ACFs with 1% HNO3and 10% H2O2had a better adsorption capacity, respectively. The adsorption amount of ACFs was affected strongly solution pH value, and decreased significantly with increasing of the pH value. The adsorption kinetics indicated that the adsorption rates of Cr6+ ion on different modified ACFs were well fitted with the pseudo-second-order kinetic model. After 1% HNO3and 10% H2O2modification, respectively, the total acidic oxygen-containing groups on ACFs surface had an increase obviously, which might be enhance the adsorption amount of Cr6+ion on ACFs.


BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 6100-6120
Author(s):  
Yinan Hao ◽  
Yanfei Pan ◽  
Qingwei Du ◽  
Xudong Li ◽  
Ximing Wang

Armeniaca sibirica shell activated carbon (ASSAC) magnetized by nanoparticle Fe3O4 prepared from Armeniaca sibirica shell was investigated to determine its adsorption for Hg2+ from wastewater. Fe3O4/ASSAC was characterized using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and BET (Brunauer–Emmett–Teller). Optimum adsorption parameters were determined based on the initial concentration of Hg2+, reaction time, reaction temperature, and pH value in adsorption studies. The experiment results demonstrated that the specific surface area of ASSAC decreased after magnetization; however the adsorption capacity and removal rate of Hg2+ increased 0.656 mg/g and 0.630%, respectively. When the initial concentration of Hg2+ solution was 250 mg/L and the pH value was 2, the adsorption time was 180 min and the temperature was 30 °C, and with the Fe3O4/ASSAC at 0.05 g, the adsorption reaching 97.1 mg/g, and the removal efficiency was 99.6%. The adsorption capacity of Fe3O4/ASSAC to Hg2+ was in accord with Freundlich isotherm models, and a pseudo-second-order kinetic equation was used to fit the adsorption best. The Gibbs free energy ΔGo < 0,enthalpy change ΔHo < 0, and entropy change ΔSo < 0 which manifested the adsorption was a spontaneous and exothermic process.


Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.


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