scholarly journals Optimizing modified rice bran for treating aqueous solutions polluted by Cr (VI) ions: isotherm and kinetics analyses

2021 ◽  
Vol 13 (SP1) ◽  
pp. 1-11
Author(s):  
Zahra Ameri ◽  
Mehran Hoodaji ◽  
Majid Rajaei ◽  
Mitra Ataabadi
Keyword(s):  
Removal Efficiency ◽  
Rice Bran ◽  
Freundlich Isotherm ◽  
Contact Duration ◽  
Isotherm Equation ◽  
Chemically Modified ◽  
Ph Values ◽  
Chromium Vi ◽  
Pseudo Second Order ◽  
Modified Adsorbents

This study investigated the possibility and efficiency of absorbing chromium (VI) (Cr [VI]) ions from the polluted solutions by employing the chemically modified adsorbents (alkali, biochar, and acid rice bran), focusing on the possible impacts of the solution’s pH values, adsorbent’s dosages, concentrations, and contact times. The colori-metric method was used for Cr determination by employing an ultraviolet/visible spectrophotometer. The scanning electron microscope and Fourier transform infrared spectroscopy were used to analyze the characteristics of the modified adsorbents. The findings indicated that the optimized acid, biochar, alkali, and unmodified rice bran removal efficiency for Cr (VI) were 94.50%, 94.27%, 88.60%, and 90.18%, respectively. The increase of adsorbent dosage up to 2 g/L led to a rise in removal effectiveness (82.06%). Furthermore, the highest removal efficiency was obtained (94%) at the pH of 2.0, the contact duration of 100 min, Cr (VI) concentration of 50 mg/L, and dosage of 2 g/L, which was statistically the optimal condition for the modified rice bran. The adsorption kinetics was agreeably suited to pseudo-second-order, whereas the Freundlich isotherm equation was also suitably expounded the study’s findings. The findings implied that the acid and biochar rice bran performed remarkably in the reme-diation of the wastewater compared with alkali rice bran for reuse for industrial, agricultural, and environmental purposes.

Biosorption of Eosin by Chemically Modified Peanut Husk

2011 ◽  
Vol 233-235 ◽  
pp. 439-443
Author(s):  
Ying Hua Song ◽  
Sheng Ming Chen
Keyword(s):  
Freundlich Isotherm ◽  
Sorption Process ◽  
Intraparticle Diffusion ◽  
Transfer Model ◽  
Experimental Conditions ◽  
Isotherm Equation ◽  
Chemically Modified ◽  
Pseudo Second Order ◽  
Uptake Studies ◽  
Rate Controlling Step

The sorption of eosin by peanut husk, which was chemically modified by formaldehyde in acidic medium was studied with variation in the parameters of contact time, pH, initial eosin concentration and temperature. They were used for equilibrium sorption uptake studies with eosin. The results indicate that sorption equilibrium could be well described by the Freundlich isotherm equation. The sorption followed the pseudo-second order model. The mass transfer model as intraparticle diffusion was applied to the experimental data to examine the mechanisms of the rate controlling step. It was found that the intraparticle diffusion is becoming the significant controlling step under the experimental conditions. The thermodynamic constants of the sorption process were also evaluated, which suggest an endothermic physical sorption process which runs spontaneously.

scholarly journals Statistical optimization and batch studies on adsorption of phosphate using Al-eggshell

2017 ◽  
Vol 36 (3-4) ◽  
pp. 999-1017 ◽  
Author(s):  
Yan Zhang ◽  
Hui Li ◽  
Yuyan Zhang ◽  
Fengjuan Song ◽  
Xiaoqiang Cao ◽  
...  
Keyword(s):  
Exothermic Reaction ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Optimal Point ◽  
Isotherm Equation ◽  
Ph Values ◽  
Phosphate Species ◽  
Pseudo Second Order ◽  
Species Removal

This work provides a simple and convenient method to manufacture the sorbent of Al-eggshell. The influence of AlCl3 concentration and pH values as well as the dosage of sorbent and their interactions on adsorption of phosphate was investigated. Therefore, Box–Behnken design coupled with response surface method was adopted to explore the empirical model for phosphate species removal. It was observed that there is an optimal point, C(AlCl3)(0.29 mol/l)–pH(6.12)–dosage(6.72 g/l), for the goal of maximizing phosphate species removal. The second-order polynomial model for phosphate reduction was given as Removal(%) = 96.43 +10.82X1 + 4.29X2 − 0.70X3 + 2.06X1X2 − 1.72X1X3 +8.24X2X3 − 13.10X12 − 17.26X22 − 1.72X32. Contour pictures implied that the interaction between pH values and sorbent dosage was the strongest, followed by C(AlCl3) versus dosage and C(AlCl3) versus pH. The adsorption of phosphate data had a good agreement with the Freundlich isotherm equation at 313 and 323 K. Otherwise, Langmuir–Freundlich model described the best fitness at the temperature of 293, 298, and 303 K. The process of adsorption of phosphate on Al-eggshell fitted a pseudo-second-order kinetic equation, which indicates the exothermic reaction. In conclusion, the present work suggests Al-eggshell as an efficient and environmental friendly sorbent for phosphate species adsorption from aqueous solutions.

scholarly journals Adsorptive Removal and Recovery of Aluminium (III), Iron (II), and Chromium (VI) onto a Low Cost Functionalized Phragmities Karka Waste

2015 ◽  
Vol 20 (2) ◽  
pp. 145-152
Author(s):  
Shukraraj Regmi ◽  
Kedar Nath Ghimire ◽  
Megh Raj Pokhrel ◽  
Deba Bahadur Khadka
Keyword(s):  
Adsorption Process ◽  
Low Cost ◽  
Volume Ratio ◽  
Freundlich Isotherm ◽  
Loading Capacity ◽  
Order Kinetic ◽  
Chemically Modified ◽  
Chromium Vi ◽  
Pseudo Second Order ◽  
Concentrated Sulfuric Acid

Chemically modified adsorbent based on Phragmities stem has been investigated by treating with concentrated sulfuric acid at 2:1 weight/volume ratio. The maximum loading capacity for Al(III) and Fe(II) onto phosphorylated charred Phragmities waste PCPW adsorbent was found to be 148 mg/g and 200 mg/g, while for Cr(VI) 200 mg/g, respectively, at their optimal pH. Similarly, it was 166.66 mg/g and 90.90mg/g for Al(III) and Fe(II) onto the charred Phragmities waste CPW, respectively. The adsorption process followed the Freundlich isotherm and pseudo-second order kinetic models. The desorption of the loaded metal ions recovery was found to be to the extent of 82%, 91% and 100% for Al(III), Fe(II) and Cr(VI), respectively.Journal of Institute of Science and Technology, 2015, 20(2): 145-152

Adsorption of Phosphorus by Lithium Silica Fume

2013 ◽  
Vol 368-370 ◽  
pp. 692-696
Author(s):  
Wei Lan Lin ◽  
Jin Chuan Gu ◽  
Yu Heng Wang ◽  
Wen Yuan Wang
Keyword(s):  
Silica Fume ◽  
Adsorption Kinetics ◽  
Removal Rate ◽  
Freundlich Isotherm ◽  
Good Method ◽  
Order Equation ◽  
Isotherm Equation ◽  
Dosage Effects ◽  
Adsorption Capacities ◽  
Pseudo Second Order

adsorption is a good method to remove phosphorus. In the experiment, lithium silica fume is used as the adsorption material, adsorption isotherms ,kinetics and dosage effects were examined. It shows that the adsorption kinetics data are consistent with the pseudo-second-order equation and the adsorption is easy to happen. Freundlich isotherm equation is fit for description of the adsorption. The maximum adsorption capacities on lithium silica fume is 1.166 mg/g. When dosage get to 12 g/l and the concentration of phosphorus solution is 2 mg/l, the removal rate reach to 95% at 308k.

scholarly journals Adsorption of As(V) from Aqueous Solution on Chitosan-Modified Diatomite

2020 ◽  
Vol 17 (2) ◽  
pp. 429 ◽  
Author(s):  
Qintao Yang ◽  
Liang Gong ◽  
Lili Huang ◽  
Qinglin Xie ◽  
Yijian Zhong ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Removal Efficiency ◽  
Ph Effect ◽  
Freundlich Isotherm ◽  
Xrd Analysis ◽  
Optimal Value ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorption Desorption ◽  
Modified Diatomite

A novel chitosan (CS)-modified diatomite (Dt) was prepared by a simple mixture in the mass ratio to remove As(V) from aqueous solution in this research. The CS-modified Dt adsorbent was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD) analysis. The parameters to influence the adsorption of As(V) ion were studied under such conditions as kinetics, adsorption isotherm, and pH effect. The results revealed that adsorption of As(V) was initially rapid and the equilibrium time was reached after 40 min. The optimal value of the pH was 5.0 for better adsorption. The equilibrium data were well fitted to the Langmuir isotherm compared to the Freundlich isotherm, and exhibited the highest capacity and removal efficiency of 94.3% under an initial As(V) concentration of 5 mg/L. The kinetic data were well described by the pseudo-second-order model. In addition, 0.1 M NaOH has the best desorption efficiency of As(V) adsorbed on CS-modified Dt, and the removal efficiency of As(V) was still higher than 90% when after six adsorption-desorption cycles. These results showed that the CS-modified Dt could be considered as a potential adsorbent for the removal of As(V) in aqueous solution.

Adsorption of chromium (VI) from aqueous solutions on activated carbon

1994 ◽  
Vol 30 (9) ◽  
pp. 191-197 ◽  
Author(s):  
R. Leyva Ramos ◽  
A. Juarez Martinez ◽  
R. M. Guerrero Coronado
Keyword(s):  
Activated Carbon ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Ph Effect ◽  
Freundlich Isotherm ◽  
Maximum Adsorption Capacity ◽  
Experimental Adsorption ◽  
Ph Values ◽  
Chromium Vi ◽  
Adsorption Data

The adsorption isotherm of chromium (VI) on activated carbon was obtained in a batch adsorber. The experimental adsorption data were fitted reasonably well to the Freundlich isotherm. The effect of pH on the adsorption isotherm was investigated at pH values of 4, 6, 7, 8, 10 and 12. It was found that at pH < 6, Cr(VI) was adsorbed and reduced to Cr(III) by the catalytic action of the carbon and that at pH ≥ 12, Cr(VI) was not adsorbed on activated carbon. Maximum adsorption capacity was observed at pH 6 and the adsorption capacity was diminished about 17 times by increasing the pH from 6 to 10. The pH effect was attributed to the different complexes that Cr(VI) can form in aqueous solution. The adsorption isotherm was also affected by the temperature since the adsorption capacity was increased by raising the temperature from 25 to 40°C. It was concluded that Cr(VI) was adsorbed significantly on activated carbon at pH 6 and that the adsorption capacity was greatly dependent upon pH.

Removal of Rhodamine B from Wastewater by Rectorite and Sepiolite-Kinetic Study and Equilibrium Isotherm Analyses

2011 ◽  
Vol 183-185 ◽  
pp. 362-366 ◽  
Author(s):  
Jun Li ◽  
Ming Zhen Hu
Keyword(s):  
Rhodamine B ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Order Kinetic ◽  
Isotherm Equation ◽  
Adsorption Removal ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

Adsorption removal of a cationic dye, rhodamine B (RhB) from water onto rectorite and sepiolite was investigated. The rectorite and sepiolite were characterized by Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). Attempts were made to fit the isothermal data using Langmuir and Freundlich equations. The experimental results have demonstrated that the equilibrium data are fitted well by a Freundlich isotherm equation. Pseudo-first-order and pseudo-second-order models were considered to evaluate the rate parameters. The experimental data were well described by the pseudo-second-order kinetic model. The results indicate that the rectorite exhibited higher adsorption capacity for the removal of RhB than sepiolite and could be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.

scholarly journals Adsorption Behaviour of Chromium(VI) onto Surface Modified Sugarcane Waste

2013 ◽  
Vol 28 (1-2) ◽  
pp. 113-122
Author(s):  
Kedar Nath Ghimire ◽  
Deepak Wagle ◽  
Suman Lal Shrestha
Keyword(s):  
Volume Ratio ◽  
Freundlich Isotherm ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Method ◽  
Chromium Vi ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Surface Modified

An effective chemically modified adsorbent based on sugarcane waste has been prepared by treating with concentrated sulphuric acid in 2:1weight/volume ratio. Thus prepared adsorbent has been found to be effective in the adsorption of chromium from aqueous medium. The efficacy of the adsorbent in the removal of chromium was evaluated by batch adsorption method. The effect of initial concentration, contact time and pH of the solution was investigated. The maximum adsorption capacity onto this adsorbent was found to be 195 mg/g at their optimal pH 1 at which unmodified bagasse has only 58 mg/g. The characterization of adsorbent was done by determining surface area and Boehm’s titration method. Freundlich isotherm and pseudo-second order kinetic model gave better explanation of the adsorption process.

scholarly journals Recent Advances in Biomass-Based Waste Materials for the Removal of Chromium (VI) from Wastewater: A Review

2021 ◽  
Vol 2 (01) ◽  
pp. 37-50
Author(s):  
Rajan Rai ◽  
Dirgha Raj Karki ◽  
Krishna Prasad Bhattarai ◽  
Bishnu Pahari ◽  
Nabina Shrestha ◽  
...  
Keyword(s):  
Literature Review ◽  
Adsorption Capacity ◽  
Environmentally Benign ◽  
Waste Materials ◽  
Health Issues ◽  
High Toxicity ◽  
Chemically Modified ◽  
Chromium Vi ◽  
Modified Adsorbents ◽  
Trace Concentrations

Hexavalent chromium (Cr(VI)) is a critical pollutant with high toxicity, even at trace concentrations. Cr(VI) is possibly carcinogenic and mutagenic and can produce serious health issues. Hence, it is necessary to remove Cr(VI) from the water before releasing it into the environment. Currently, numerous removal techniques were used. Adsorption is the best method compared to others because it is simple, cheap, highly efficient, and can be used in water having trace concentrations of contaminants. Biomass-based waste materials (BMWs) are found as far better adsorbents than commercially and other available adsorbents. In this study, the existing Cr(VI) removal techniques are reviewed and, a broad range of current research studies of Cr(VI) removal from water by using BMWs are evaluated. This review can be helpful to develop a more efficient, cheap, reliable, and environmentally benign bio-adsorbent. It is obvious after the literature review given herein that BMWs exhibited potential adsorbents for the removal of Cr(VI). Also, the chemically modified adsorbents exhibited a higher adsorption capacity than unmodified adsorbents.

scholarly journals Response surface methodology as a statistical tool for optimization of removal of chromium (VI) from aqueous solution by Teff (Eragrostis teff) husk activated carbon

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Tsegaye Adane ◽  
Daniel Haile ◽  
Awrajaw Dessie ◽  
Yohannes Abebe ◽  
Henok Dagne
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Removal Efficiency ◽  
Carbon Adsorbent ◽  
Statistical Tool ◽  
Chromium Vi ◽  
Environment Exposure ◽  
Column Adsorption ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

AbstractRecently, rapid industrialization leads to excessive release of heavy metals such as Cr(VI) in the environment. Exposure to chromium (VI) can cause kidney and liver damage, depressed immune systems, and a variety of cancers. Therefore, treatment of Cr(VI) containing wastewater is mandatory. This study aims to optimize the removal of Cr(VI) from aqueous solution using locally available Teff husk activated carbon adsorbent. The laboratory-based study was conducted on the optimization of Cr(VI) removal efficiency of Teff husk activated carbon from aqueous solution. A central composite design was used to examine the effect of the interaction of process parameters and to optimize the process using Design Expert version 7.0 software. The optimized removal efficiency of Teff husk activated carbon (95.597%) was achieved at 1.92 pH, 87.83 mg/L initial concentration, 20.22 g/L adsorbent dose, and 2.07 H contact time. The adsorption of Cr(VI) on Teff husk activated carbon was found to be best fitted with pseudo-second-order kinetics and Langmuir isotherm model of the adsorption. Teff husk activated carbon can be used as an efficient adsorbent for removal of chromium (VI) from contaminated water. Column adsorption needs to be studied in the future.

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