Desorption of Phenol from Activated Carbon by Hot Water Regeneration. Desorption Isotherms

Solar energy is an attractive energy source among various renewable energy resources in Malaysia as relatively high solar radiation is available throughout the year. This solar energy can be utilized for air-conditioning by using solar-powered adsorption refrigeration cycle. Intermittent nature of the solar radiation leads to a challenge for continuous air-conditioning operation. In the present study, a combination of solar-powered adsorption refrigeration system and thermal storage is studied. Activated carbon-ammonia and activated carbon-methanol are the working pairs of the adsorption reaction. Analytical calculation results show that activated carbon-methanol pair indicates higher coefficient of performance (COP) than activated carbon-ammonia pair, while adsorption chiller system with hot water thermal storage has higher COP than the system with ice thermal storage. For the activated carbon-methanol case with hot water thermal storage, the COP is 0.79. Since this COP analysis is based on the ideal case with uniform temperature distribution within the reactor beds, which achieves equilibrium states at the end of the reactions. In more realistic situation, the reaction process will be terminated before reaching to the equilibrium states because of the non-uniform temperature distribution and the time required for the reaction. Transient simulation in which heat transfer and reaction equation are combined will be performed to model actual reactors.

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Adsorption behaviour and mechanism of the PFOS substitute OBS (sodium p -perfluorous nonenoxybenzene sulfonate) on activated carbon

Royal Society Open Science ◽

10.1098/rsos.191069 ◽

2019 ◽

Vol 6 (9) ◽

pp. 191069 ◽

Cited By ~ 3

Author(s):

Wei Wang ◽

Xin Mi ◽

Huilan Shi ◽

Xue Zhang ◽

Ziming Zhou ◽

...

Keyword(s):

Particle Size ◽

Activated Carbon ◽

Pore Size ◽

Adsorption Capacity ◽

Organic Pollutant ◽

Chemical Properties ◽

Hot Water ◽

Adsorption Behaviour ◽

Adsorption Capacities ◽

Naoh Solution

Perfluorooctane sulfonate (PFOS) was listed as a persistent organic pollutant by the Stockholm Convention. As a typical alternative to PFOS, sodium p -perfluorous nonenoxybenzene sulfonate (OBS) has recently been detected in the aquatic environment which has caused great concern. For the first time, the adsorption behaviour and mechanism of OBS on activated carbon (AC) with different physical and chemical properties were investigated. Decreasing the particle size of AC can accelerate its adsorption for OBS, while AC with too small particle size was not conducive to its adsorption capacity due to the destruction of its pore structure during the mechanical crushing process. Intra-particle diffusion had a lesser effect on the adsorption rate of AC with smaller particle size, higher hydrophilicity and larger pore size. Reactivation of AC by KOH can greatly enlarge their pore size and surface area, greatly increasing their adsorption capacities. The adsorption capacity of two kinds of R-GAC exceeded 0.35 mmol g −1 , significantly higher than that of other ACs. However, increasing the hydrophilicity of AC would decrease their adsorption capacities. Further investigation indicated that a larger pore size and smaller particle size can greatly enhance the adsorptive removal of OBS on AC in systems with other coexisting PFASs and organic matter due to the reduction of the pore-blocking effect. The spent AC can be successfully regenerated by methanol, and it can be partly regenerated by hot water and NaOH solution. The percentage of regeneration for the spent AC was 70.4% with 90°C water temperature and up to 95% when 5% NaOH was added into the regeneration solution. These findings are very important for developing efficient adsorbents for the removal of these newly emerging PFASs from wastewater and understanding their interfacial behaviour.

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A Downdraft Fixed-Bed Biomass Gasification System with Integrated Products of Electricity, Heat, and Biochar: The Key Features and Initial Commercial Performance

Energies ◽

10.3390/en12152979 ◽

2019 ◽

Vol 12 (15) ◽

pp. 2979 ◽

Cited By ~ 2

Author(s):

Huang ◽

Wan ◽

Liu ◽

Zhang ◽

Ma ◽

...

Keyword(s):

Activated Carbon ◽

Fixed Bed ◽

Energy Resource ◽

Clean Energy ◽

Biomass Gasification ◽

Vital Role ◽

Hot Water ◽

Apricot Kernel ◽

Key Features ◽

Downdraft Fixed Bed

Biomass, as a renewable and clean energy resource, plays a vital role in energy security and greenhouse gas reduction across the world. This paper reports on our newly established technology: a downdraft fixed-bed biomass gasification system using nut shells (mainly apricot kernel shells) for electricity generation, heating and partially activated carbon production at the same time. Particularly, the key features of the gasification reactor will be presented in detail. In the commercial plant (3 MW scale) located in Hebei province, China, the typical energy conversion from apricot kernel shell gasification is as follows: 47% syngas, 44% char (partially activated carbon), 5% hot water, and 4% energy loss. The main gasification temperature is 600–800 °C, while the activation zone is 850–900 °C. The commercial system has currently been in operation for 4 years. Considering the partially activated carbon as a stable carbon carrier, the whole system features negative CO2 emissions.

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Adsorption and desorption of perchloroethylene in soils, peat moss, and granular activated carbon

Canadian Journal of Civil Engineering ◽

10.1139/l89-123 ◽

1989 ◽

Vol 16 (6) ◽

pp. 798-806 ◽

Cited By ~ 7

Author(s):

Richard Zytner ◽

Nihar Biswas ◽

Jatinder K. Bewtra

Keyword(s):

Activated Carbon ◽

Granular Activated Carbon ◽

Freundlich Isotherm ◽

Peat Moss ◽

Organic Carbon Content ◽

Dry Cleaning ◽

Desorption Process ◽

The Media ◽

Desorption Isotherms ◽

Adsorption Desorption

Studies were conducted to evaluate the adsorption–desorption isotherms of a common dry cleaning solvent, perchloroethylene (PCE), in soils, peat moss, and granular activated carbon. The results obtained followed the Freundlich Isotherm, and the organic carbon content of the media was the most significant controlling factor in the adsorption–desorption process. The peat moss exhibited the highest residual saturation concentration for pure PCE amongst all the media tested. The desorption studies indicated that PCE had medium mobility in soil and was not significantly affected by moderate changes in pH. Key words: adsorption, desorption, Freundlich Isotherm, granular activated carbon, peat moss, perchloroethylene, soils.

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Experimental and Theoretical Study of the Energy Flow of a Two Stages Four Generators Adsorption Chiller

Al-Khwarizmi Engineering Journal ◽

10.22153/kej.2018.01.002 ◽

2019 ◽

Vol 14 (2) ◽

pp. 129-136

Author(s):

Faeza Mahdi Hadi

Keyword(s):

Activated Carbon ◽

Cold Water ◽

Water Cycle ◽

Electrical Power ◽

Hot Water ◽

Coefficient Of Performance ◽

Cooling Power ◽

Low Grade ◽

Adsorption Chiller ◽

Two Stages

This work is concerned with a two stages four beds adsorption chiller utilizing activated carbon-methanol adsorption pair that operates on six separated processes. The four beds that act as thermal compressors are powered by a low grade thermal energy in the form of hot water at a temperature range of 65 to 83 °C. As well as, the water pumps and control cycle consume insignificant electrical power. This adsorption chiller consists of three water cycles. The first water cycle is the driven hot water cycle. The second cycle is the cold water cycle to cool the carbon, which adsorbs the methanol. Finally, the chilled water cycle that is used to overcome the building load. The theoretical results showed that average cycle cooling power is 2.15kW, while the experimental measurement revealed that the cooling capacity of the cycle is about 1.98 kW with a relative error of % 0.02. The generator and condensing temperatures are 83 and 30 °C, respectively. The coefficient of performance (COP) of that chiller was in the range of 0.37 to 0.49. The best operating point and the best working conditions were also investigated. The present chiller is superior more than the single stage, two beds adsorption chiller that works on the activated carbon methanol pair that needs a high ambient temperature.

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