Effect of solution pH and influence of water hardness on caffeine adsorption onto activated carbons

2014 ◽  
Vol 93 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Osorio Moreira Couto ◽  
Inês Matos ◽  
Isabel Maria da Fonseca ◽  
Pedro Augusto Arroyo ◽  
Edson Antônio da Silva ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Water Hardness ◽  
Solution Ph ◽  
Influence Of Water

scholarly journals Oxytetracycline Adsorption from Aqueous Solutions on Commercial and High-Temperature Modified Activated Carbons

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3481
Author(s):  
Joanna Lach ◽  
Agnieszka Ociepa-Kubicka ◽  
Maciej Mrowiec
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Activated Carbons ◽  
Electricity Consumption ◽  
Solution Ph ◽  
Carbon Modification ◽  
Modification Method ◽  
Flow Through ◽  
Proposed Modification ◽  
Modified Activated Carbons

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.

Comparison of Coal Ash and Activated Carbon for Removal of Humic Acid from Aqueous Solution

2013 ◽  
Vol 864-867 ◽  
pp. 1509-1512
Author(s):  
Xue Mei Zhang ◽  
Yan Zhang ◽  
Di Fan
Keyword(s):  
Aqueous Solution ◽  
Humic Acid ◽  
Activated Carbons ◽  
Removal Rate ◽  
Coal Ash ◽  
Cost Effective ◽  
Solution Ph ◽  
Adsorption Behaviors ◽  
Calcium Loading ◽  
Working Solution

This paper presents the adsorption behaviors of humic acid (HA) on coal ashes and powdered activated carbons (PACs). A bituminous coal, with or without calcium-loading, was used as a feedstock for coal ash preparation. The working solution of HA with a concentration of 20 mg/L was used in all adsorption tests. The results showed that calcium-enriched coal ash (CECA) gave rise to the removal rate of HA as high as 84.05%, much higher than those of raw coal ash (RCA) and PACs. The impacts of solution pH and adsorbent dosage on HA adsorption capacity were also investigated. It was found that lower pH facilitated to the removal of HA from aqueous solution by means of CECA, and the optimal CECA dosage was about 1.0g/L at pH 7.00. The data obtained in this study suggested that calcium-enriched coal ash could be useful and cost-effective in the treatment of wastewaters containing HA-like organic macro-molecules.

scholarly journals Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

2019 ◽  
Author(s):  
Lorena Alcaraz ◽  
María Esther Escudero ◽  
Francisco J. Alguacil ◽  
Irene Llorente ◽  
Ana Urbieta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Activated Carbons ◽  
Chemical Study ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Microporous Material ◽  
Physico Chemical ◽  
Spent Coffee Ground ◽  
Coffee Ground

This paper describes the physico-chemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. KOH activated carbon is a microporous material with a specific BET surface area of 2330 m2·g-1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g-1. A significant dependence of the adsorption capacity on the solution pH was found, while it does not depend significantly neither on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g-1 and 33.52 mg·g-1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better fit to a Langmuir model and a pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous and favorable process.

scholarly journals An alternative low-cost adsorbent for gold recovery from cyanide-leached liquors: Adsorption isotherm and kinetic studies

2018 ◽  
Vol 37 (1-2) ◽  
pp. 3-23 ◽  
Author(s):  
Refiloe Tsolele ◽  
Fanyana Moses Mtunzi ◽  
Michael John Klink ◽  
Vusumzi Emmanuel Pakade
Keyword(s):  
Activated Carbons ◽  
Selective Adsorption ◽  
Low Cost ◽  
Kinetic Studies ◽  
Agitation Speed ◽  
Gold Recovery ◽  
Attractive Alternative ◽  
Solution Ph ◽  
Initial Concentration ◽  
Modified Activated Carbons

Pristine Macadamia nutshell-based activated carbons were chemically oxidized with different concentrations of H3PO4 and HNO3 to increase their surface adsorption properties and further explore if they could be an attractive alternative low-cost adsorbent for gold recovery from cyanide-leached liquors. The modified activated carbons were labeled MACN20, MACN40 and MACN55 to signify the materials prepared from 20%, 40% and 55% (v/v) HNO3, respectively. Similar nomenclature was followed for H3PO4-modified activated carbons. Brunauer-Emmet-Teller, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, elemental analysis and X-ray diffraction spectroscopy were used to characterize the prepared activated carbons. The physical properties were attained through determining attrition, ash content, volatile matter and moisture content of all the activated carbons. Various parameters that affect selective adsorption such as the effect of initial concentration, time, agitation speed, interfering species and the dose of the adsorbent were investigated. Optimal parameters for gold ion adsorption were as follows: solution pH, 10; contact time, 6 h; agitation speed, 150 r/min; sorbent amount, 4 g and initial concentration, 5.5 mg/L. The observed selectivity order was not the same for all the adsorbents, but the adsorption of gold was found to be mostly influenced in the presence of nickel and least influenced by copper. MACN55 was found to be the most efficient adsorbent with 74% of gold adsorption from a real-world sample and displayed a similar performance to coconut-based activated carbons.

scholarly journals Influence of Water on the Dynamic Adsorption of Chlorinated VOCs on Active Carbon: Relative Humidity of the Gas Phase versus Pre-Adsorbed Water

2006 ◽  
Vol 24 (3) ◽  
pp. 215-228 ◽  
Author(s):  
F. Cosnier ◽  
A. Celzard ◽  
G. Furdin ◽  
D. Bégin ◽  
J.F. Marêché
Keyword(s):  
Gas Phase ◽  
Activated Carbons ◽  
Adsorbed Water ◽  
Phase Versus ◽  
Chlorinated Volatile Organic Compounds ◽  
Adsorption Capacities ◽  
Volatile Organic ◽  
Influence Of Water ◽  
Hindered Diffusion ◽  
Induced Adsorption

The present work deals with the influence of water on the adsorption of two chlorinated volatile organic compounds (VOCs) on activated carbons (ACs) having very different pore textures and surface chemistry. Two kinds of moisture were considered, viz. pre-adsorbed on the AC or present as steam in the gaseous phase, at various relative humidities ranging from 30% to 75%. It is shown that the adsorption of the VOCs depends on the kind of moisture. If the latter is pre-adsorbed, water is just displaced by the VOCs (overshoot). The adsorption capacities of the AC remain unchanged and only some minor changes in the shape of the breakthrough front, corresponding to hindered diffusion, may sometimes occur. In contrast, the simultaneous adsorption of steam and VOC leads to competition between water and the chlorinated compound, with direct consequences on the adsorption kinetics and capacities of the AC. However, the decrease of the water-induced adsorption performances depends strongly on the AC and the VOC (through different VOC/AC and water/VOC interactions), and on the concentration of the VOC.

Influence of Water Hardness and Co-applied Herbicides on Saflufenacil Efficacy

2012 ◽  
Vol 11 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Jared M. Roskamp ◽  
Gurinderbir S. Chahal ◽  
William G. Johnson
Keyword(s):  
Water Hardness ◽  
Influence Of Water

scholarly journals Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1372 ◽  
Author(s):  
Lorena Alcaraz ◽  
María Esther Escudero ◽  
Francisco José Alguacil ◽  
Irene Llorente ◽  
Ana Urbieta ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Potassium Hydroxide ◽  
Activated Carbons ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Microporous Material ◽  
Spent Coffee Ground ◽  
Coffee Ground ◽  
Pseudo Second Order

This paper describes the physicochemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. Potassium hydroxide (KOH)-activated carbon is a microporous material with a specific Brunauer–Emmett–Teller (BET) surface area of 2330 m2·g−1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g−1. A significant dependence of the adsorption capacity on the solution pH was found, but it does not significantly depend on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g−1 and 33.52 mg·g−1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better a fit to the Langmuir model and pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous, and favorable process.

Quinone/hydroquinone redox couple as a source of enormous capacitance of activated carbon electrodes

2013 ◽  
Vol 1505 ◽  
Author(s):  
Krzysztof Fic ◽  
Mikolaj Meller ◽  
Grzegorz Lota ◽  
Elzbieta Frackowiak
Keyword(s):  
Activated Carbon ◽  
Redox Reactions ◽  
Electrode Materials ◽  
Activated Carbons ◽  
Hydroxyl Group ◽  
Carbon Surface ◽  
Carbon Electrodes ◽  
Main Subject ◽  
Solution Ph ◽  
Reversible Redox

ABSTRACTThe main subject of this paper is to examine and to evaluate the capacitive behaviour of activated carbon electrodes electrochemically decorated by quinone-type functional groups. For this purpose, different electrolytes, i.e. hydroquinone, catechol and resorcinol at the concentration of 0.38 mol L-1, dissolved in 1 mol L-1 H2SO4, 1 mol L-1 Li2SO4 and 6 mol L-1 KOH were used. These electrolytes could generate electroactive groups (able to undergo reversible redox reactions) on the surface of electrode material. Apart from typical adsorption of the mentioned dihydroxybenzenes, so called grafting could occur and might cause generation of quinone|hydroquinone functionals on carbon surface. As an effect of functional reversible redox reaction, additional capacitance value, called pseudocapacitance, could be achieved. Hence, besides typical charge originating from charging/discharging of the electrical double layer on the electrode/electrolyte interface, additional capacitance comes also from faradaic reactions. Activated carbons are the most promising electrode materials for this purpose; apart from great physicochemical properties, they are characterized by well-developed specific surface area over 2000 m2 g-1 which results in high capacitance values.In the manuscript the influence of the hydroxyl group location as well as electrolyte solution pH on the electrochemical performance of the electrode is discussed.

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