scholarly journals OPTIMIZATION OF ULTRASONICALLY ASSISTED ADSORPTION OF Cu(II) ON CARBONIZED AND ACTIVATED WALNUT SHELLS

Author(s):  
Dragan Milenković ◽  
Milutin Milosavljević ◽  
Aleksandar Bojić

The effects of ultrasound (US) on the adsorption process of Cu(II) on granulated activated carbon (GAC), produced by walnut shells, was studied in this paper. Equilibrium results of the adsorption process are tested by Freundlich and Langmuir adsorption isotherms, and their linearization and determination of model parameters k; n; b and Qo. The adsorption capacity of GAC is 1.7 to 3.86 mmol/g with the use of US, and 0.66 to 2.7 mmol /g without the use of US. The increase of specific surface and initial concentration increase the efficacy of adsorption. Acquired mathematical regression equations very well represent experimental results, and the correlation coefficient (R2) is greater than 0.993.

2019 ◽  
Vol 14 (4) ◽  
pp. 897-907 ◽  
Author(s):  
Hosseinali Asgharnia ◽  
Hamidreza Nasehinia ◽  
Roohollah Rostami ◽  
Marziah Rahmani ◽  
Seyed Mahmoud Mehdinia

Abstract Phenol and its derivatives are organic pollutants with dangerous effects, such as poisoning, carcinogenicity, mutagenicity, and teratogenicity in humans and other organisms. In this study, the removal of phenol from aqueous solution by adsorption on silica and activated carbon of rice husk was investigated. In this regard, the effects of initial concentration of phenol, pH, dosage of the adsorbents, and contact time on the adsorption of phenol were investigated. The results showed that the maximum removal of phenol by rice husk silica (RHS) and rice husk activated carbon (RHAC) in the initial concentration of 1 mgL−1 phenol, 2 gL−1 adsorbent mass, 120 min contact time, and pH 5 (RHS) or pH 6 (RHAC) were obtained up to 91% and 97.88%, respectively. A significant correlation was also detected between increasing contact times and phenol removal for both adsorbents (p < 0.01). The adsorption process for both of the adsorbents was also more compatible with the Langmuir isotherm. The results of this study showed that RHS and RHAC can be considered as natural and inexpensive adsorbents for water treatment.


2015 ◽  
Vol 802 ◽  
pp. 425-430
Author(s):  
Muhd Nazmi Ismail ◽  
Hamidi Abdul Aziz ◽  
Mohd Azmier Ahmad ◽  
Nik Athirah Yusoff

In this present study, rubber seed-coated activated carbon (RSCAC) was used as a natural adsorbent to remove basic (MB), acid (MR) and reactive (RBV) dyes using batch process. Each dye in the adsorption process was tested at different initial concentration from 50-500 mg/l. Different dyes showed different percentage removals. The highest removal was recorded by MB which was up to 99.9 %. The experimental data was analyzed with Langmuir and Freundlich adsorption models. The data fitted well with Langmuir. The adsorption capacity were 332.99, 210.33 and 155.37 mg/g for MB, MR and RBV, respectively.


1998 ◽  
Vol 16 (7) ◽  
pp. 557-564 ◽  
Author(s):  
Jinben Wang ◽  
Yao Lu ◽  
Buxing Han ◽  
Ming Dai ◽  
Haike Yan ◽  
...  

This paper describes the hydrophobic effect in the process of adsorption of alkyltrimethylammonium bromides from aqueous solution on to an activated carbon surface. Measurements of the adsorption isotherms of a series of alkyltrimethylammonium bromides with different hydrocarbon tail lengths at the activated carbon surface were carried out. In order to investigate the temperature dependence of the adsorption process, the determination of the adsorption of cetyltrimethylammonium bromide (CTAB) was undertaken at different temperatures in the range 20–60°C. From the experimental results obtained, the relevant thermodynamic quantities have been calculated. The role played by the hydrophobic effect in the adsorption process of cationic surfactants on to activated carbon and the factors affecting the adsorption mechanism were discussed.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2900
Author(s):  
Alejandro Aldeguer Esquerdo ◽  
Pedro José Varo Galvañ ◽  
Irene Sentana Gadea ◽  
Daniel Prats Rico

In this study, the reduction of the pesticide simazine at an initial concentration of 0.7 mg L−1 in water has been investigated using two different technologies: adsorption with powdered and granulated activated carbon, advanced oxidation processes with ozone and finally, the combination of both technologies. The results obtained for a carbon dose of 16 mg L−1 show that powdered activated carbon, with contact times of 60 min, obtained 81% of reduction and in 24 h 92%, while granulated activated carbon at 60 min obtained a reduction of 2%, rising to 34% after 24 h of contact time. Therefore, powdered activated carbon achieves better reductions compared to granulated; when ozone was applied at a dose of 19.7 mg L−1, with a reaction time of 18 min, a reduction of 93% was obtained, achieving a better reduction in less time than with adsorption treatments; however, during oxidation, by-products of simazine were produced. In the combined treatments, with the same doses of carbon and ozone mentioned above, the treatment that starts with ozone followed by activated carbon powder is recommended due to the adsorption in the last phase reaching a 90% reduction of the simazine and its by-products in 38 min of time.


2012 ◽  
Vol 610-613 ◽  
pp. 1710-1717
Author(s):  
Gui Zhong Zhou ◽  
Xuan Wang ◽  
Zhao Feng Wang ◽  
Shu Qing Pan ◽  
Shao Xiang Li

The activated carbon fiber(ACF) electrodes were prepared for electrosorption desalination. The electrodes were analyzed using scanning electron microscope (SEM), and the desalting efficiency was represented by the removal rate of Cl-. As a result, desalting efficiency decreases with increasing initial concentration of Cl-, whereas the total adsorption capacity increases. The most suitable voltage for electrosorption desalination is 1.2 ~ 1.4V. The electrosorption desalination achieves the best results while the distance between two electrodes is 1.0cm. Electrosorption plays a more important role in the adsorption process compared with physical adsorption. The removal rate of Cl- is obviously improved by using ACF electrode modified by HNO3 and KOH and desalination ratio of the electrode treated with KOH is increased by 16.5%. Therefore, the ACF electrode would be suitable for using in the application of electrosorption desalination.


Author(s):  
Ishaq Yahaya Lawan ◽  
Shinggu D. Yamta ◽  
Abdurrahman Hudu ◽  
Kolo Alhaji Madu ◽  
Adamu Mohammad ◽  
...  

This study was carried out to evaluate the efficiency of metals (Pb and Co) removal from solution using Detarium microcarpum seeds as adsorbent. The effect of initial concentration and adsorbent dosage on the adsorption process of these metals were studied, the percentage removal of these metals increased with increased in weight (0.5 -2.5g) in 50ml of the solution and the adsorption efficiency increased with increasing initial metal ion concentration (0.01-0.05 moldm−3). The percentage removal obtained for Lead and Cobalt were compared. The result of adsorption were fitted to Langmuir models and coefficients indicated favorable adsorption of Pb2+ and Co2+ ions on the adsorbents. The adsorption of Pb2+ and Co2+ in aqueous solution was in the following order (1400µm>420µm>150µm). More than 55.4% of studied Lead cations were removed by 1400µm, 47.2% by 420µm and 29.8% by 150µm. While for Cobalt cations only 53.2% by 1400µm, 38.6% by 420µm and 24% by 150µm respectively, from aqueous solution it was concluded that, activated Carbon derived from Detarium microcarpum seed is good in removing both lead and cobalt ions, which make it good absorbent.


Author(s):  
Nguyen Thanh Tam ◽  
Nguyen Hoai Phuong Duy ◽  
Tran Thi Phuong Thuy ◽  
Võ Thi Thanh Tien ◽  
Tran Cong Khanh

In this study, adsorbent materials from natural feldspar were fabricated for application in +NH4 removal. Raw, pretreated by HCl 3M, and modified feldspar by NaOH and aluminum (Al powder, Al(OH)3, and AlCl3.6H2O) were used. Feldspar was modified under different experimental conditions including without calcination and calcinated at 500ºC and 700ºC. The influence of various operating parameters consisting of material size, adsorption time, +NH4 initial concentration and material dosage were investigated. Adsorbent materials < 0.1 mm in size showed the highest adsorption efficiency. Subsequently materials with size of < 0.1 mm were used for the following studies to investigate the affect of other parameters on +NH4 adsorption process. The highest removal efficiency (31.10%) and removal capacity (21.80 mg/g) were obtained by modified feldspar by NaOH and AlCl3.6H2O with calcination at 700ºC at +NH4 initial concentration of 5 ppm. Results from the scanning electron microscope (SEM) showed the differences on surfaces of adsorption materials. Modified feldspar had a clean surface and more tiny pores compared to those of raw and pretreated feldspar resulting in an increased surface area. Consequently +NH4 adsorbent efficiency and removal capacity were increased. By BET (Brunauer, Emmett and Teller) the specific surface areas of adsorbent materials were analyzed and the surface areas of raw, pretreated and modified feldspar were 0.484 m2/g, 0.988 m2/g and 2.024 m2/g, respectively. +NH4 adsorbent mechanisms of all raw, pretreated, and modified feldspar materials were found to follow the Langmuir adsorption isotherm with the correlation coefficient R2 = 0.989 which described the monolayer type of the adsorption.


Author(s):  
BAC HOANG BUI ◽  
Võ Thị Hạnh ◽  
Lê Thị Duyên ◽  
Nguyễn Thị Thanh Thảo ◽  
Khương Thế Hùng ◽  
...  

Thach Khoan, Phu Tho area is the area with great potential for weathered kaolinite source from pegmatites of the Tan Phuong complex. This kaolin has quite good quality and is used in many traditional applications such as high quality ceramic glaze, high-grade bricks. However, the use of this material in the treatment of water pollution is still limited. In this study, the natural kaolin material from Thach Khoan area, Phu Tho province with about 87% amount of tubular halloysites was used to remove Cd2+ ion from water. The factors of pH, contact time, the adsorbent weight, and initial concentration of Cd2+ were studied to access their effects on the Cd2+ ion adsorption process using this raw material. The results indicated that under the conditions of pH0 of 6.5 and at room temperature (25 oC), with 0.8 g of halloysite powder and Cd2+ initial concentration of 30 mg/L, the adsorption of Cd2+ could reach equilibrium after 50 minutes with an efficiency of 86.31%. The adsorption process follows the Langmuir adsorption isotherm model with the maximum monolayer adsorption capacity of 2.75 mg/g and follows the second-order pseudo-adsorption kinetic equation. The results show that the natural halloysite material without treatment has the potential in using to remove heavy metal ions in polluted water and needs to be studied further.


2011 ◽  
Vol 356-360 ◽  
pp. 2616-2619
Author(s):  
Li Yi Ye ◽  
Xiao Xuan Zhang ◽  
Ying Wu Yin ◽  
Song Tu ◽  
Yong Sha

The performance of activated carbon (AC) adsorption process for the treatment of a simulated wastewater of fuchsin basic dye was investigated. The experiment revealed that under the optimum adsorption conditions (initial concentration of wastewater 250 mg L-1of dye, temperature 25 °C and AC dosage 4 g L-1), the color removal efficiency was 98% after 360 min of adsorption. As for the further use of AC, the saturated AC was regenerated by heated 20 min at 600 °C in the atmosphere of N2. Efficiency of regeneration was 99% and the regeneration loss was less than 5%. It indicated that AC was effective in the decolorization of dye wastewater.


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