Removal of Cr (VI) from Aqueous Solution Using Camellia oleifera Abel Shells

2013 ◽  
Vol 743-744 ◽  
pp. 463-468
Author(s):  
Yu Dong Lu ◽  
Wen Lu Wu ◽  
Shan Lin ◽  
Rui Yun You ◽  
Zong Hua Wu

The use of camellia oleifera abel shells as biosorbent has been successfully demonstrated in the removal of Cr (VI) from aqueous solution. The effects of different parameters, such as, contact time, initial concentration of Cr (VI), pH and temperature on Cr (VI) adsorption were investigated. The results showed that the maximum uptake of Cr (VI) was up to 190.69 mg/g at a pH value of around 1.0, under the initial Cr (VI) concentration of 400mg/L and at the temperature of 298 K. The adsorption kinetics could be described by pseudo-first order and pseudo-second order kinetics models.

Author(s):  
C.E. Muko-Okoro ◽  
I.A. Obiora-Okafo ◽  
J.N. Ndive

Phenol is a prevalent pollutant found in many industrial wastewaters, and it is paid singular attention because of its special features including high toxicity, carcinogenic properties, and vital cumulative ability that affects the health of humans and the environment. The current study investigated the removal of phenol from synthetic aqueous solutions using prepared Moringaoleifera seed shell as an adsorbent. The efficiency of phenol removal by Moringaoleifera seed shell was evaluated in a batch system, and different parameters such as initial concentration of phenol (100, 200, 300, 400 and 500 mg/L), contact time (10, 20, 30, 40, 50 and 60 min), and adsorbent dosage (0.2, 0.4, 0.6, 0.8, and 1.0 g) were studied. The results showed that the highest percentage of phenol removal by the ash occurred at 0.8 g dosage, contact time of 40 min, and initial concentration of 500 mg/L giving 87.2% phenol removal. The adsorption process was modeled with Langmuir and Freundlich isotherms and adsorption kinetics (pseudo-first order and pseudo-second order) at controlled temperatures. The results showed that the experimental data fitted the Langmuir (R2 = 0.8338) much better than the Freundlich model (R2 = 0.7314). For the analysis of the adsorption kinetics, the results showed that the experimental data fitted the pseudo-second order kinetics (R2 = 0.999) much better than the pseudo-first order kinetics (R2 = 0.5042). In general, the results of this study revealed that Moringaoleifera seed shell has suitable potential for use in removing phenol from aqueous solution on operation and practical scales due to its availability and organic nature.


2020 ◽  
Vol 82 (11) ◽  
pp. 2592-2602
Author(s):  
Zhengji Yi ◽  
Jian Liu ◽  
Rongying Zeng ◽  
Xing Liu ◽  
Jiumei Long ◽  
...  

Abstract Camellia oleifera shell-based activated carbon (COSAC) was prepared by H3PO4 activation method and further used to remove U(VI) from the aqueous solution in a batch system. This research examined the influence of various factors affecting U(VI) removal, including contact time, pH, initial U(VI) concentration, and temperature. The results showed that the U(VI) adsorption capacity and removal efficiency reached 71.28 mg/g and 89.1% at the initial U(VI) concentration of 160 mg/L, temperature of 298 K, pH 5.5, contact time of 60 min, and COSAC dosage of 2.0 g/L. The pseudo-first-order, pseudo-second-order, and intraparticle diffusion equations were used to identify the optimum model that can describe the U(VI) adsorption kinetics. The pseudo-second-order kinetics model performed better in characterizing the adsorption system compared with the pseudo-first-order and intraparticle diffusion models. Isotherm data were also discussed with regard to the appropriacy of Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models. The Langmuir model described the U(VI) adsorption process the best with a maximum adsorption capacity of 78.93 mg/g. Thermodynamic analysis (ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0) indicated that the U(VI) adsorption process is endothermic and spontaneous. All the results imply that COSAC has a promising application in the removal or recovery of U(VI) from aqueous solutions.


2020 ◽  
Vol 3 (6) ◽  
pp. 857-870
Author(s):  
Shagufta Zafar ◽  
Muhammad Imran Khan ◽  
Mushtaq Hussain Lashari ◽  
Majeda Khraisheh ◽  
Fares Almomani ◽  
...  

AbstractThe present study investigates the removal of copper ions (Cu (II)) from aqueous solution using chemically treated rice husk (TRH). The chemical treatment was carried out using NaOH solution and the effect of contact time (tc), adsorbent dosage (Dad), initial Cu (II) concentration ([Cu]i), and temperature (T) on the percentage removals of Cu (II) (%RCu) were investigated. Different analytical techniques (FTIR, SEM, and EDX) were used to confirm the adsorption (ads) of Cu (II) onto the TRH. The ads kinetics was tested against pseudo-first-order (PFO) and pseudo-second-order (PSO) models as well as Langmuir and Freundlich isotherms. Treating RH with NaOH altered the surface and functional groups, and on the surface of RH, the ionic ligands with high electro-attraction to Cu increased and thus improved the removal efficiency. The %RCu decreased by increasing the [Cu]i and increased by increasing the ct, Dad, and T. Up to 97% Cu removal was achieved in ct of 30 min using Dad of 0.3 g [Cu]i of 25 mg L−1 and T = 280 K. The ads of Cu on TRH is endothermic, spontaneous, follows Langmuir isotherms, and exhibited a PSO kinetics. Moreover, the TRH was successfully regenerated and used for further adsorption cycles using 1 M HNO3.


2021 ◽  
Author(s):  
Thi-Thuy Luu ◽  
Duy-Khoi Nguyen ◽  
Tu Thi Phuong Nguyen ◽  
Thien-Hoang Ho ◽  
Van-Phuc Dinh ◽  
...  

Abstract To remove Ni(II) ions from an aqueous solution, researchers used red mud modified by chitosan (RM/CS) material as a new adsorbent. According to the findings, the surface area of red mud is nearly doubled after being treated with chitosan, from 68.6 m2/g to 105.7 m2/g. The effects of pH solution, contact time, and material dosage on the Ni(II) uptake were examined. In comparison with the pseudo-first-order and pseudo-second-order models, the intra-diffusion model was the most suitable kinetic model for the Ni(II) removal. Besides, the three-parameter Sips model was used to predict the Ni(II) adsorption of RM/CS from aqueous solution. Furthermore, the Langmuir maximum Ni(II) uptake capacity of this material was 31.66 mg/g at 323K, which was higher than red mud and several other natural materials. Notably, thermodynamic investigations demonstrated that Ni(II) adsorption on RM/CS is both exothermic and physic.


2015 ◽  
Vol 93 (10) ◽  
pp. 1083-1087 ◽  
Author(s):  
Ali Issa Ismail

Graphene is a newly discovered material and is considered to be the new wonder material for many applications. The recent possibility of obtaining pure and fully characterized graphene opens the door to the study of the adsorption of toxic materials on graphene. The adsorption behavior of p-nitrophenol on graphene was studied in aqueous medium. The effect of each of pH, temperature, and dosage was emphasized. The highest calculated adsorption capacity of 4-nitrophenol was found to be 15.5 mg/g, assuming Langmuir fitting starting from 11.1 mg/g initial concentration at 298 K and pH = 6. Fitting the data using the Freundlich isotherm model predicted a favorable adsorption process (n > 1). The rise and saturation areas of the isotherms were fitted as pseudo first-order and pseudo second-order processes, respectively, with relatively good fit (k1 = 0.0023/s, k2 = 0.68 g mg−1 s−1). The thermodynamic properties indicated a spontaneous and exothermic process.


Author(s):  
C. Obi ◽  
N. C. Ngobiri ◽  
L. C. Agbaka ◽  
M. U. Ibezim-Ezeani

The study focused on the investigation of the effectiveness of the pericarp of monkey kola (Cola lepidota) biomass (CLPB) in the removal of toluene from aqueous system. X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and phytochemical screening methods were used for characterizing the biosorbent. The effects of contact time, pH, and concentration on biosorption process were studied. The phytochemical screening showed the presence of alkaloids, flavonoids, tannins, carbohydrate, saponins and steroids. Carboxylic, alkene and alcohol groups were found to be the principal functional groups. The highest percentage removal was 99.63% at toluene initial concentration of 40 mg/L and 98.30% at pH 8. The contact time 30 minutes gave better removal efficiency of 99.89%. Among the biosorption isotherm models tested (Langmuir, Freundlich, Dubinin Radushkevich and Temkin, respectively), the Langmuir model equation gave a better fit of the equilibrium data with a correlation coefficient (R2) of 0.99. The equilibrium data was tested with pseudo-first order and pseudo-second order models and pseudo-second order model (R² = 0.99) fitted more than the pseudo-first order model (R² = 0.85). This study has revealed that Cola lepidota is a potential biosorbent for the removal of toluene from aqueous medium under the operating conditions of contact time of 30 minutes, pH of 8 and initial concentration of 40 mg/g.


Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1141 ◽  
Author(s):  
Joanna Lach

The aim of the study was to evaluate the possibility of applying commercial activated carbons currently used in water treatment plants and modified carbon at 400 and 800 °C in the atmosphere of air, water vapour and carbon dioxide to remove chloramphenicol. Adsorption kinetics was examined for solutions with pH of 2–10. Adsorption kinetics were determined for the initial concentration of chloramphenicol of 161 mg/dm3 and the adsorption isotherm was determined for the concentrations of 161 to 1615 mg/dm3. Of the analysed activated carbons (F-300, F-100, WG-12, ROW 08 Supra and Picabiol), the highest adsorption capacity was obtained for the use of Picabiol (214 mg/g), characterized by the highest specific surface area and pore volume. The pH value of the solution has little effect on the adsorption of chloramphenicol (the highest adsorption was found for pH = 10, qm = 190 mg/g, whereas the lowest—for pH = 6, qm = 208 mg/g). Modification of activated carbon WG-12 at 800 °C caused an increase in adsorption capacity from 195 mg/g (unmodified carbon) to 343 mg/g. A high correlation coefficient was found between the capacity of activated carbons and the total volume of micropores and mesopores. Among the examined adsorption kinetics equations (pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion), the lowest values of the R2 correlation coefficient were obtained for the pseudo-first order equation. Other models with high correlation coefficient values described the adsorption kinetics. The adsorption results were modelled by means of the Freundlich, Langmuir, Temkin and Dubibin–Radushkevich adsorption isotherms. For all activated carbons and process conditions, the best match to the test results was obtained using the Langmuir model, whereas the lowest was found for the Dubibin–Radushkevich model.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Faranak Pishgar ◽  
Homayon Ahmad Panahi ◽  
Ali Akbar Khodaparast Haghi ◽  
Vahid Motaghitalab ◽  
Amir Hesam Hasani

Diazinon and chlorpyrifos are two common organophosphorus poisons to fight the pests in Iran. The removal of these poisons from water by thermosensitive nanosphere polymer (TNP), synthesized from the copolymerization of N-isopropylacrylamide and 3-allyloxy-1,2-propanediol, was investigated. The effect of pH, contact time, and the initial concentration on the removal amount was studied. The highest removal amount of these poisons by TNP occurred at pH 7. The contact time increase improves the removal amount and the equilibrium contact time for diazinon and chlorpyrifos was 10 and 18 min, respectively. For low concentration of less than 50 mgL−1it was shown that removal capacity remains above 95%. The initial concentration above 50 mgL−1decreased the removal amount, in which chlorpyrifos showed a greater decrease. The kinetic data has been checked using pseudo first-order, pseudo second-order, and intraparticle diffusion equations. The intraparticle diffusion model had the best conformability for the adsorption process.


2021 ◽  
Author(s):  
khaled Mostafa ◽  
H. Ameen ◽  
A. Ebessy ◽  
A. El-Sanabary

Abstract Our recently tailored and fully characterized poly (AN)-starch nanoparticle graft copolymer having 60.1 G.Y. % was used as a starting substrate for copper ions removal from waste water effluent after chemical modification with hydroxyl amine via oximation reaction. This was done to change the abundant nitrile groups in the above copolymer into amidoxime one and the resultant poly (amidoxime) resin was used as adsorbent for copper ions. The resin was characterized qualitatively via rapid vanadium ion test and instrumentally by FT-IR spectra and SEM morphological analysis to confirm the presence of amidoxime groups. The adsorption capacity of the resin was done using the batch technique, whereas the residual copper ions content in the filtrate before and after adsorption was measured using atomic adsorption spectrometry. It was found that the maximum adsorption capacity of poly (amidoxime) resin was 115.2 mg/g at pH 7, 400ppm copper ions concentration and 0.25 g adsorbent at room temperature. The adsorption, kinetics and isothermal study of the process is scrutinized using different variables, such as pH, contact time, copper ion concentration and adsorbent dosage. Different kinetics models comprising the pseudo-first-order and pseudo-second-order have been applied to the experimental data to envisage the adsorption kinetics. It was found from kinetic study that pseudo-second-order rate equation was better than pseudo-first-order supporting the formation of chemisorption process. While, in case of isothermal study, the examination of calculated correlation coefficient (R2) values showed that the Langmuir model provide the best fit to experimental data than Freundlich one.


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