scholarly journals Ultrasonic Regeneration Studies on Activated Carbon Loaded with Isopropyl Alcohol

2020 ◽  
Vol 10 (21) ◽  
pp. 7596
Author(s):  
Hsuan-Yi Hong ◽  
Niels Michiel Moed ◽  
Young Ku ◽  
Hao-Yeh Lee

Ultrasonic regeneration of activated carbon loaded with isopropyl alcohol (IPA) was studied. IPA adsorption was performed batchwise at varying solution pH. Adsorption was optimal at solution pH 7, which was closest to the point of zero charge of the activated carbon (6.7). Ultrasonic regeneration was performed on IPA-loaded activated carbon with three factors being tested: ultrasonic intensity, solution temperature and ethanol addition. Regeneration efficiency increased with ultrasonic intensity up to 32.4 W/cm2. A higher intensity led to a higher desorption but damaged the activated carbon, shown by a decrease in the particle size of activated carbon. The regeneration efficiency increased with solution temperature primarily because desorption is endothermic and because the surface tension and viscosity of a solution are reduced with increasing temperature, promoting cavitation bubble production. Ethanol addition increased regeneration efficiency up to 10%, as ethanol reduces tensile stress, facilitating cavitation bubble generation. At 15% and above, regeneration decreases, possibly due to coalescence of bubbles into larger, more stable bubbles. Under optimal parameters, the regeneration efficiency was 83%, which dropped to 64% after four regeneration cycles.


2020 ◽  
Vol 15 ◽  
pp. 155892502091984
Author(s):  
Moussa Abbas ◽  
Zahia Harrache ◽  
Mohamed Trari

This study investigates the potential use of activated carbon, prepared from pomegranate peels, as an adsorbent activated using H3PO4 and its ability to remove crystal violet from an aqueous solution. The adsorbent was characterized by the Brunauer–Emmett–Teller method (specific surface area: 51.0674 m2 g−1) and point of zero charge (pHPZC = 5.2). However, some examined factors were found to have significant impacts on the adsorption capacity of activated carbon derived from pomegranate peels such as the initial dye concentration (5–15 mg L−1), solution pH (2–14), adsorbent dose (1–8 g L−1), agitation speed (100–700 r/min), and temperature (298–338 K). The best adsorption capacity was found at pH 11 with an adsorbent dose of 1 g L−1, an agitation speed at 400 r/min, and a contact time of 45 min. The adsorption mechanism of crystal violet onto activated carbon derived from pomegranate peels was studied using the pseudo-first-order, pseudo-second-order, Elovich, and Webber–Morris diffusion models. The adsorption kinetics were found to rather follow a pseudo-second order kinetic model with a determination coefficient ( R2) of 0.999. The equilibrium adsorption data for crystal violet adsorbed onto activated carbon derived from pomegranate peels were analyzed by the Langmuir, Freundlich, Elovich, and Temkin models. The results indicate that the Langmuir model provides the best correlation with qmax capacities of 23.26 and 76.92 mg g−1 at 27°C and 32°C, respectively. The adsorption isotherms at different temperatures have been used for the determination of thermodynamic parameters like the free energy, enthalpy, and entropy to predict the nature of adsorption process. The negative values Δ G0 (−5.221 to −1.571 kJ mol−1) and Δ H0 (−86.141 kJ mol−1) indicate that the overall adsorption is spontaneous and exothermic with a physisorption process. The adsorbent derived from pomegranate peels was found to be very effective and suitable for the removal of reactive dyes from aqueous solutions, due to its availability, low-cost preparation, and good adsorption capacity.



2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ibrahim A. Amar ◽  
Salma M. Hassan ◽  
Fatima H. Aqeela ◽  
Mohamed Y. Najem ◽  
Fatima A. Altohami

Purpose This paper aims to investigate the potential application of Balanites aegyptiaca bark powder (BABP) for removing a basic textile dye, methylene blue (MB), from aqueous solutions. Design/methodology/approach The biosorbent (BABP) was characterized using Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pHPZC). Batch mode was selected to study the biosorption of MB onto BABP surface at different experimental conditions (shaking speed, contact time, initial solution pH, ionic strength, solution temperature, biosorbent dosage and initial dye concentration). Besides, the reusability of BABP for MB biosorption was also examined. Findings The biosorption results revealed that approximately 96% of MB was removed successfully at the optimized operational conditions. Pseudo-second-order and Langmuir models, respectively, better described the adsorption kinetics and isotherms. The monolayer biosorption capacity (qmax) for MB was about 97.09 mg/g. According to thermodynamics findings, the MB biosorption onto BABP is an exothermic and spontaneous process. The results demonstrate that BABP can be considered as potential eco-friendly, readily available and low-cost biosorbent for hazardous textile dyes removal from water bodies and also provides a promising method for minimization of agricultural solid wastes (e.g. plant barks). Originality/value The utilization of Balanites aegyptiaca bark powder (BABP), solid waste material, as low-cost and eco-friendly biosorbent for the removal of hazardous basic textile dye (methylene blue) from the aquatic environment.



2018 ◽  
Vol 2017 (3) ◽  
pp. 686-694 ◽  
Author(s):  
Hangdao Qin ◽  
Rong Xiao ◽  
Renhui Zhang ◽  
Jing Chen

Abstract Adsorption is an efficient treatment process to remove benzoic acid from aqueous solution. In this study, nitrogen-containing surface groups were introduced onto activated carbon (AC) surface by modification with ammonium hydroxide, ammonium carbonate, melamine or urea. The nitrogen-containing AC samples were characterized using N2 adsorption-desorption, Boehm titration, determination of the pH of the point of zero charge (pHpzc) and X-ray photoelectron spectroscopy. The adsorption of benzoic acid from aqueous solution by nitrogen-containing AC has been studied. The Langmuir model fitted the experimental data of equilibrium isotherms better than the Freundlich model. At initial solution pH 2.1, the adsorption capacity was closely related with the amount of pyridinic and pyrrolic N on the AC surface, which indicated these two nitrogen-containing groups played an important part in the adsorption process. The enhancement of adsorption capacity was due to the strengthened π–π dispersion force between benzoic acid and the AC basal plane. Since the surface charge of AC as well as the existence form of benzoic acid varied with solution pH value, the adsorption capacity was found to be highest at pH 3.8 and dropped sharply at higher or lower pH values.



2021 ◽  
Vol 17 (1) ◽  
pp. 95-103
Author(s):  
Mohamad Firdaus Mohamad Yusop ◽  
Mohd Azmier Ahmad ◽  
Nur Ayshah Rosli ◽  
Fadzil Noor Gonawan ◽  
Soran Jalal Abdullah

Physiochemical activation consists of heat treatment coupling with CO2 gasification and KOH chemical treatment were applied in preparing durian peel based activated carbon (DPAC) to remove basic dye, malachite green (MG) from aqueous solution. Several parameters namely, effect of initial MG concentration as well as contact time, solution temperature and initial solution pH were carried out in this study. Characterization study revealed that DPAC pose high BET surface area which is 886.31 m2/g and its surface was found to be mesoporous in nature with heterogeneous type of pore structures. Eight isotherms and four kinetic models were utilized and it was revealed that the adsorpttion system followed Freundlich isotherm and pseudo-first order (PFO) kinetic model. Mechanism study using intraparticle diffusion and Boyd plot confirmed that adsorption of MG onto DPAC was controlled by the film-diffusion mechanism. Thermodynamic study indicated that the adsorption system was exothermic, spontaneous, feasible and governed by physical-type of adsorption.



2013 ◽  
Vol 319 ◽  
pp. 245-248 ◽  
Author(s):  
Yi Ke Li ◽  
Ya Dong Wang ◽  
Yang Zhang ◽  
Run Ping Han ◽  
Yan Qiang Li

The adsorption studies of 4-chlorophenol from aqueous solution on activated carbon derived from wheat straw (WAC) have been performed. Several experimental parameters like initial pH, p-CP concentration and solution temperature were evaluated. Solution pH within 2-8 is favor of adsorption and it is disadvantage of adsorption at higher temperature. Langmuir and Freundlich isotherm models were used to fit the experimental data and Langmuir was better. The maximum capacity was 64.8 mg g–1 at 293 K. The process is spontaneous and exothermic and physical action is major mechanism.



This present study focuses on the synthesis of a new modified eco-friendly adsorbent, spent tea (ST, discarded Camellia sinensis leaves), and its application in the adsorption of Aspirin from aqueous solution by batch adsorption technique. This is an effort in shifting towards new substitutes that are both inexpensive and highly efficient, such as agricultural waste materials as an alternative of the commonly used adsorbent material, activated carbon. The ST will first undergo an acid treatment using phosphoric acid, and subsequently modified with Polyethyleneimine (PEI) using Glutaraldehyde (GA) as the cross-linker. Aspirin removal efficiency was compared between the untreated spent tea (ST) and new PEI modified acid treated spent tea (TA-PEI). Effects of ratio of acid treated spent tea (TA) and PEI (1:1, 1:2,1:3, 2:1,3:1), and GA concentration (0,0.5,1.0,2.0,3.0, and 4.0 v/v%) were investigated. The optimal conditions for the synthesis of the modified adsorbent, TA-PEI are TA: PEI ratio of 1:2, and 0.5(v/v %) of GA. Afterwards, the untreated ST and TA-PEI were tested to determine the effect of contact time on Aspirin adsorption. It was found that TA-PEI shows great removal effectiveness - up to 64.70% before reaching equilibrium after 30min of contact time. Nevertheless, ST only shows removal of 1% and after 15min, there is no appreciable adsorption. These results suggested that TA-PEI has high potential to be used as an effective adsorbent for Aspirin removal. In the future, TA-PEI will undergo further research to investigate the effects of different adsorbent dosage, solution pH, initial concentration, solution temperature, and contact time. Several analysis (FTIR, SEM, CHNS, BET and point of zero charge) has to be done as well to get a better understanding of its properties and the adsorption mechanisms



2013 ◽  
Vol 807-809 ◽  
pp. 582-590
Author(s):  
Zi Cheng Yi ◽  
Shi Ming Luo ◽  
Gen Li ◽  
Hua Shou Li ◽  
Hui Min Lin

The adsorption characteristics of Cr(VI) on activated carbon prepared from several agriculture by-products via sulphuric acid-treatment were compared and the best concentration of sulphuric acid for carbonization were evaluated. It is confirmed that peanut shell is best material for the absorption of Cr(VI) ion from aqueous solution among hybrid giant napier straw, rice husk and commercial activated carbon in this study. The effects of agitation time, solution pH, temperature and Cr(VI) initial concentration on Cr(VI) adsorption were investigated. The 3:1 volume ratio of sulphuric acid : deionized water is the optimal concentration for Cr(VI) biosorption for peanut shell carbonization. Cr(VI) adsorption is highly dependent on solution pH. Initial solution pH =1.5 was the most favorable pH for Cr(VI) removal. Cr(VI) biosorption increases with increasing initial concentration, agitation time and solution temperature. The adsorption kinetics is found well fitted to the pseudo-second-order kinetic model. The adsorption equilibrium data are best represented by Langmuir model.The maximum adsorption capacity of carbonized peanut shell for Cr(VI) reached 26.22 mg/g.



2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Mohd Azhar Ahmad ◽  
Safarudin Gazali Herawan ◽  
Ahmad Anas Yusof

The adsorption of remazol brilliant blue R (RBBR) dye on pinang frond based activated carbon (PF-AC) was investigated in a batch process. The effects of initial dye concentration, contact time, solution temperature, and solution pH were evaluated. The adsorption equilibrium and kinetic were found to follow Freundlich isotherm models and pseudo-second-order kinetic model, respectively. The mechanism of the adsorption process was found from the intraparticle diffusion model. Result from adsorption thermodynamic show that interaction for RBBR dye was found to be feasible, nonspontaneous, and endothermic. The results indicated that the PF-AC is very effective for the RBBR adsorption from aqueous solution.



2014 ◽  
Vol 5 (8) ◽  
pp. 3061-3070 ◽  
Author(s):  
Yohei Kotsuchibashi ◽  
Ravin Narain

Dual-temperature and pH responsive (ethylene glycol)-based nanogels were synthesized. Both the core and the shell of the nanogels showed a lower critical solution temperature (LCST) and the LCST of the shell was strongly affected by the solution pH and salt concentration due to the presence of carboxylic acid groups at the nanogel surface.



Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3481
Author(s):  
Joanna Lach ◽  
Agnieszka Ociepa-Kubicka ◽  
Maciej Mrowiec

The aim of the work was to evaluate the possibility of using commercial and modified activated carbons for the removal of oxytetracycline from aqueous solutions. The kinetics and statics of adsorption as well as the effect of the activated carbon dose and solution pH on the efficiency of the oxytetracycline adsorption were analyzed. Based on the study of oxytetracycline adsorption isotherms, the activated carbons were ranked in the following order: F-300 > WG-12 > Picabiol > ROW08 > WACC 8 × 30 > F-100 > WAZ 0.6–2.4. The most effective activated carbons were characterized by large specific surfaces. The best matching results were obtained for: Redlich–Peterson, Thot and Jovanovic models, and lower for the most frequently used Freundlich and Langmuir models. The adsorption proceeded better from solutions with pH = 6 than with pH = 3 and 10. Two ways of modifying activated carbon were also assessed. A proprietary method of activated carbon modification was proposed. It uses the heating of activated carbon as a result of current flow through its bed. Both carbons modified at 400 °C in the rotary kiln and on the proprietary SEOW (Joule-heat) modification stand enabled to obtain adsorbents with higher and comparable monolayer capacities. The advantage of the proposed modification method is low electricity consumption.



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