scholarly journals Single-Stage Microwave-Assisted Coconut-Shell-Based Activated Carbon for Removal of Dichlorodiphenyltrichloroethane (DDT) from Aqueous Solution: Optimization and Batch Studies

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Azrina Aziz ◽  
Mohamad Nasran Nasehir Khan ◽  
Mohamad Firdaus Mohamad Yusop ◽  
Erniza Mohd Johan Jaya ◽  
Muhammad Azan Tamar Jaya ◽  
...  

This research aims to optimize preparation conditions of coconut-shell-based activated carbon (CSAC) and to evaluate its adsorption performance in removing POP of dichlorodiphenyltrichloroethane (DDT). The CSAC was prepared by activating the coconut shell via single-stage microwave heating under carbon dioxide, CO2 flow. The total pore volume, BET surface area, and average pore diameter of CSAC were 0.420 cm3/g, 625.61 m2/g, and 4.55 nm, respectively. The surface of CSAC was negatively charged shown by the zeta potential study. Response surface methodology (RSM) revealed that the optimum preparation conditions in preparing CSAC were 502 W and 6 min for radiation power and radiation time, respectively, which corresponded to 84.83% of DDT removal and 37.91% of CSAC’s yield. Adsorption uptakes of DDT were found to increase with an increase in their initial concentration. Isotherm study revealed that DDT-CSAC adsorption system was best described by the Langmuir model with monolayer adsorption capacity, Qm of 14.51 mg/g. The kinetic study confirmed that the pseudo-second-order model fitted well with this adsorption system. In regeneration studies, the adsorption efficiency had slightly dropped from 100% to 83% after 5 cycles. CSAC was found to be economically feasible for commercialization owing to its low production cost and high adsorption capacity.

2012 ◽  
Vol 599 ◽  
pp. 614-617 ◽  
Author(s):  
Zi Jun Tang ◽  
Chao Ping Cen ◽  
Ping Fang ◽  
Yang Ming Liang

In this study, a sewage sludge-base activated carbon (SSAC) was prepared by means of ZnCl2 chemical activation-pyrolysis-carbonization. Different factors such as activated temperature, activators, additives, sludge/activation solution ratio, activated time and other factors which affecting SSAC characteristics were studied to obtain the optimal preparation conditions. The result shows that when using 3mol/L zinc chloride with the ratio of zinc chloride to sulfuric acid as 10:1(v/v), activated at 550°C with the ratio of sludge to activation solution as 1:4(w/v) for 1 hour of pyrolysis and the rate of N2 was set at 0.5L/min, the BET surface area, total pore volume and average pore diameter of the SSAC was 469.80m2/g, 0.16cm3/g and 2.60nm respectively. Using SSAC to treat simulating wastewater containing 100mg(Ni2+)/L, the removal rate of Ni2+ was 20.59% with the adsorption capacity of 10.57mg/g. When the pH>10.5 the removal efficiency approached 100%.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 257
Author(s):  
Jie Ren ◽  
Nanwei Chen ◽  
Li Wan ◽  
Guojian Li ◽  
Tao Chen ◽  
...  

In this study, a new method for economical utilization of coffee grounds was developed and tested. The resulting materials were characterized by proximate and elemental analyses, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption–desorption at 77 K. The experimental data show bio-oil yields reaching 42.3%. The optimal activated carbon was obtained under vacuum pyrolysis self-activation at an operating temperature of 450 °C, an activation temperature of 600 °C, an activation time of 30 min, and an impregnation ratio with phosphoric acid of 150 wt.%. Under these conditions, the yield of activated carbon reached 27.4% with a BET surface area of 1420 m2·g−1, an average pore size of 2.1 nm, a total pore volume of 0.747 cm3·g−1, and a t-Plot micropore volume of 0.428 cm3·g−1. In addition, the surface of activated carbon looked relatively rough, containing mesopores and micropores with large amounts of corrosion pits.


2009 ◽  
Vol 79-82 ◽  
pp. 1907-1910
Author(s):  
Zhi Gang Xie

Porous activated carbon was prepared from orange wastes using zinc chloride as an activating agent by one-step carbonization method. Effects of impregnation ratio, carbonization temperature and heat preservation time on pore characteristics of activated carbon were studied. The porous structures of the orange wastes activated carbon were investigated by BET, D-R equations, BJH equations and Kelvin theory. The morphology was observed using transmission electron microscopy (TEM). The mesoporous activated carbon is gained when the impregnation ratio is 3:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has total pore volume 2.098 cm3/g, mesoporous pore volume 1.438 cm3/g, with a high BET surface area 1476m2/g. The pore distribution of the mesoporous activated carbon is very concentrative, with average pore diameter of 3.88nm. While, the high specific surface area activated carbon is gained when the impregnation ratio is 2:1; the carbonization temperature is 550°Cand heat preservation time is 1.0 h. The activated carbon has high BET surface area 1909 m2/g, while the total pore volume is only 1.448cm3/g and microporous pore volume is 0.889cm3/g, with average pore diameter of 2.29 nm.


BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 614-621
Author(s):  
Qingsong Ji ◽  
Haichao Li ◽  
Jingjing Zhang

The object of this study was to prepare activated carbons containing nitrogenous functional groups by a chemical method from nitrogen-containing raw materials. Fish (Ctenopharyngodon idellus) scales were impregnated with phosphoric acid (H3PO4) and activated at varied temperatures. The adsorption ability, structural characteristics, surface chemistry, and morphology of the activated carbons were characterized by methylene blue and iodine values, nitrogen adsorption, the Boehm method, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The total alkaline groups content of the activated carbon produced from fish scales was 0.4330 mmol/g, the total acidic groups was 1.68 mmol/g, the Brunauer–Emmett–Teller (BET) surface area was 501 cm2/g, and the total pore volume was 0.284 cm3/g. The average pore diameter was 1.94 nm under an activation temperature of 550 °C, an activation time of 1 h, and an impregnation ratio of 2. As a result of this study, nitrogenous functional groups that contained acid-base amphoteric adsorbent were produced.


2021 ◽  
Vol 18 (4) ◽  
pp. 109-118
Author(s):  
Kalpana Patidar ◽  
Manish Vashishtha ◽  
Sonal Rajoria ◽  
Tarun Kumar Chaturvedi

The present work is focussed on treating dye-laden polluted water by using a mustard straw-based activated carbon prepared using ZnCl2 and H3PO4 activation methods. The activation conditions based on the parameters reported in the literature are taken as follows: 700 °C activation temperature, impregnation ratio 2.0, and heating time 2 h. The textural and surface properties of mustard stalk activated carbon (MSAC) were studied by using SEM, nitrogen adsorption, and FT-IR, whereas its adsorption capacity was obtained using the methylene blue (MB) adsorption method. Activation of ZnCl2 and H3PO4 resulted in a BET surface area of 402 and 496 m2/g, respectively. The average pore diameter of the MSAC was found to be 2.13 and 2.59 nm for ZnCl2 and H3PO4 activation respectively. The Langmuir and Freundlich models were applied to evaluate the equilibrium parameters of MB adsorption. The monolayer adsorption capacity of MSAC by ZnCl2 and H3PO4 for MB removal from the Langmuir model were 122.25 and 213.21 mg/g respectively. Activation with H3PO4 was found to be more effective in modifying the structure of the mustard straw when compared with ZnCl2 and also it resulted in a higher adsorption capacity of MB. The present work highlights that the MSAC produced using H3PO4 activation is a low-cost bio-based adsorbent using abundant agricultural by-product namely mustard straw, and this adsorbent can be used in numerous industrially important applications.


Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 545
Author(s):  
Nurul Noramelya Zulkefli ◽  
Mohd Shahbudin Masdar ◽  
Wan Nor Roslam Wan Isahak ◽  
Siti Nur Hatika Abu Bakar ◽  
Hassimi Abu Hasan ◽  
...  

Hydrogen sulfide (H2S) should be removed in the early stage of biogas purification as it may affect biogas production and cause environmental and catalyst toxicity. The adsorption of H2S gas by using activated carbon as a catalyst has been explored as a possible technology to remove H2S in the biogas industry. In this study, we investigated the optimal catalytic preparation conditions of the H2S adsorbent by using the RSM methodology and the Box–Behnken experimental design. The H2S catalyst was synthesized by impregnating commercial activated carbon (CAC) with zinc acetate (ZnAc2) with the factors and level for the Box–Behnken Design (BBD): molarity of 0.2–1.0 M ZnAc2 solution, soaked temperature of 30–100 °C, and soaked time of 30–180 min. Two responses including the H2S adsorption capacity and the BET surface area were assessed using two-factor interaction (2FI) models. The interactions were examined by using the analysis of variance (ANOVA). Hence, the optimum point of molarity was 0.22 M ZnAc2 solution, the soaked period was 48.82 min, and the soaked temperature was 95.08 °C obtained from the optimum point with the highest H2S adsorption capacity (2.37 mg H2S/g) and the optimum BET surface area (620.55 m2/g). Additionally, the comparison of the optimized and the non-optimized catalytic adsorbents showed an enhancement in the H2S adsorption capacity of up to 33%.


2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Joumana Toufaily ◽  
Bachar Koubaissy ◽  
Lina Kafrouny ◽  
Hussein Hamad ◽  
Patrick Magnoux ◽  
...  

AbstractWater pollution by toxic organic compounds is a problem and demand for efficient adsorbents for the removal of toxic compounds is increasing. In the present work, we studied the functionalization of SBA-15 materials via the co-condensation between an alkoxysilane and an organoalkoxysilane in the presence of P123 as structuring agent. Several types of ligands were used: 3-mercaptopropylmethyldimethoxysilane, N-[3-(trimethoxysilyl) propyl] aniline; aminopropyltrimethoxysilane; [aminoethylamino]-propyltrimethoxysilanes and [(2-aminoethylamino) ethylamino] propyltrimethoxysilanes. These materials exhibit BET surface area of 275–776 m2/g and total pore volume of 0.29–1 cm3/g, depending on the ligand types and contents. Elementary analysis results confirm the incorporation of both thiol and amine group in the materials. Batch adsorption studies shows that the adsorption capacity of phenol drifts on the amine and thiol functionalized SBA-15 is greater than that on pure SBA-15. A linear relationship was observed between the adsorption capacity and N/SiO2 ratio. It was shown that the presence of amine promotes interactions with water molecules, on the other hand, these results can also be explained by the basic behavior of N-functionalized materials.


2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).


2020 ◽  
Vol 38 (9-10) ◽  
pp. 450-463
Author(s):  
Xiya Li ◽  
Jieqiong Qiu ◽  
Yiqi Hu ◽  
Xiaoyuan Ren ◽  
Lu He ◽  
...  

The production of low-cost biologically activated carbons (BACs) is urgent need of environmental protection and ecological sustainability. Hence, walnut shells were treated by traditional pyrolysis, direct KOH impregnation and combined activation composed of hydrothermal carbonization and two-step H3PO4- and pyrolysis-activation process to obtain porous carbon with high adsorption capacity. It was found that the best adsorption capacity for iodine and organic dye methylene blue (MB) can be obtained using the KOH impregnation at impregnation ratio of 1:1 or combined activation comprising of 2 h H3PO4 activation and 1 h pyrolysis activation at 1000°C. The produced KOH, H3PO4/pyrolysis activated BACs at the optimum conditions are superior to that of commercial ACs, 9.4 and 1.3 times for MB removal, 4 and 4.5 times for iodine number respectively. Characterization results demonstrated their porous structure with very good textural properties such as high BET surface area (1689.1 m2/g, 1545.3 m2/g) and high total pore volume (0.94 cm3/g, 0.96 cm3/g). The N2 adsorption-desorption isotherm of H3PO4/pyrolysis activated hydrochar suggested the co-existence of micro and meso-pores. Moreover, they are more effective for the removal of Fe(III) and Cr(VI) from aqueous solution than the commercial AC, suggesting a promising application in the field of water treatment.


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