Experimental Study on Dynamic Adsorption of Xenon over Adsorbents

2013 ◽  
Vol 739 ◽  
pp. 142-147
Author(s):  
Guo Li He ◽  
Hong Hong Yi ◽  
Xiao Long Tang ◽  
Fen Rong Li ◽  
Yun Dong Li ◽  
...  

Selecting effective xenon adsorbents is important for preventing significant global nuclear proliferation. The adsorption capacity of coconut shell activated carbons (SAC),zeolite 10X,zeolite 5A, zeolite 13X were researched and the Xenon adsorption of the coconut shell activated carbon modified by KOH(SAC/KOH-1 and SAC/KOH-2) were compared in this paper. The factors of temperature and flow rate that influenced the dynamic adsorption of xenon by 10X were discussed. The order of the Xenon adsorption capacity is as follows: zeolite 10X, SAC/KOH-2, SAC/KOH-1, SAC, zeolite 13X, zeolite 5A.

2010 ◽  
Vol 160-162 ◽  
pp. 1239-1244
Author(s):  
Wei Lu ◽  
Zheng Yuan Hong ◽  
Jun Xia Yu ◽  
Jia Guo

In this paper, coconut-shell activated carbons (CSAC) used as the carrier of nicotinic acid (VPP) and the process of controlled release of VPP were studied. CSACs with relatively high yield and good adsorptive capacity prepared by CO2 activation method under the condition of 850oC, 1.5h activation time and 1.5L/min CO2 flow rate, were used as the VPP carrier. Langmuir model was suitable for describing the process of CSAC adsorbing VPP, and the maximum adsorptive capacity of CSAC was 136.32mg/g. The cumulative release percentages of VPP in distilled water, simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were 22.53%, 45.86% and 53.94%, respectively. Higuchi model was the most suitable for describing the processes of CSAC releasing of VPP in the different media.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 201
Author(s):  
Chaiyot Tangsathitkulchai ◽  
Suravit Naksusuk ◽  
Atichat Wongkoblap ◽  
Poomiwat Phadungbut ◽  
Prapassorn Borisut

The equilibrium and kinetics of CO2 adsorption at 273 K by coconut-shell activated carbon impregnated with sodium hydroxide (NaOH) was investigated. Based on nitrogen adsorption isotherms, porous properties of the tested activated carbons decreased with the increase of NaOH loading, with the decrease resulting primarily from the reduction of pore space available for nitrogen adsorption. Equilibrium isotherms of CO2 adsorption by activated carbons impregnated with NaOH at 273 K and the pressure up to 100 kPa displayed an initial part of Type I isotherm with most adsorption taking place in micropores in the range of 0.7–0.9 nm by pore-filling mechanisms. The amount of CO2 adsorbed increased with the increase of NaOH loading and passed through a maximum at the optimum NaOH loading of 180 mg/g. The CO2 isotherm data were best fitted with the three-parameter Sips equation, followed by Freundlich and Langmuir equations. The pore diffusion model, characterized by the effective pore diffusivity (De), could well describe the adsorption kinetics of CO2 in activated carbons impregnated with NaOH. The variation of De with the amount of CO2 adsorbed showed three consecutive regions, consisting of a rapid decrease of De for CO2 loading less than 40 mg/g, a relatively constant value of De for the CO2 loading of 40–80 mg/g and a slow decrease of De for the CO2 loading of 80–200 mg/g. The maximum De occurred at the optimum NaOH loading of 180 mg/g, in line with the equilibrium adsorption results. The values of De varied from 1.1 × 10−9 to 5.5 × 10−9 m2/s, which are about four orders of magnitude smaller than the molecular diffusion of CO2 in air. An empirical correlation was developed for predicting the effective pore diffusivity with the amount of CO2 adsorbed and NaOH loading.


Author(s):  
Hind Yaacoubi ◽  
Zuo Songlin

Abstract The objective of this research is to study the retention of two acidic anthraquinone dyes by Coconut-shell-based activated carbon. Ultimately, this work allows the valorization of this new material as an adsorbent. The effect of ammonia modification on the adsorption capacity of activated carbon towards remazol brilliant blue R19 (RB19) and acid blue 25 (AB25), has been studied. Coconut-shell-based activated carbon material was modified under ammonia flow at 900 and 1000 °C. The adsorption rates and isotherms of RB19 and AB25 on the resultant materials were then tested. The results show that ammonia modification remarkably increases the adsorption capacities of the activated carbons to RB19 and AB25, by a factor of 2–3 after treatment at 1000 °C (From 0.22 mmol g−1 and 1.04 mmol g−1 to 0.76 mmol g−1 and 2.19 mmol g−1 on AC and AC-O-N-1000, respectively). The increased adsorption capacity is attributed to the introduction of basic nitrogen-containing functional groups and enhanced pore development by ammonia modification. The collected experimental kinetic and isotherm data are well compatible with the intraparticle diffusion kinetic model and the Langmuir isotherm model. According to these results, the adsorption affinity is homogeneous in terms of surface functional groups and the surface bears a finite number of identical adsorption sites.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Le Phuong Hoang ◽  
Huu Tap Van ◽  
Thi Thuy Hang Nguyen ◽  
Van Quang Nguyen ◽  
Phan Quang Thang

Coconut shell activated carbon loaded with cobalt ferrite (CoFe2O4) composites (CAC/CoFe2O4) was synthesized via the single-step refluxing router method to manufacture adsorbents. The adsorbents were then applied to remove Rhodamine B (RhB) from aqueous environments via adsorption. The properties of coconut shell activated carbon (CAC) and CAC/CoFe2O4 were investigated through the usage of electron microscopic methods (SEM: Scanning Electron Microscopy, EDS: Energy Dispersive X-ray), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). A series of batch experiments were implemented to evaluate the influences of various experimental parameters (initial pH, RhB concentration, contact time, and dosage of CAC/CoFe2O4) on the adsorption process. It was found that CoFe2O4 was successfully attached to activated carbon particles and had the suitable adsorption capacity for RhB at a molar ratio of 1 : 2:200 corresponding to the Co : Fe:CAC order. The removal efficiency and adsorption of RhB were optimal at a pH level of 4. The maximum adsorption capacity was 94.08 mg/g at an initial concentration of 350 mg/L and adsorbent dosage of 0.05 g/25 mL. Freundlich and Langmuir's models fitted well with the results obtained from the experimental data. The pseudo-second-order model also suited the most for RhB adsorption with the most remarkable correlation coefficient (R2 = 0.934). The adsorption process was controlled by a chemisorption mechanism through electrostatic attraction, hydrogen bonding interactions, and π-π interactions.


RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22892-22899 ◽  
Author(s):  
Qiang Liu ◽  
Ming Ke ◽  
Feng Liu ◽  
Pei Yu ◽  
Haiqiang Hu ◽  
...  

Nitrogen-rich coconut shell activated carbons were prepared with high CH3SH capacity and easy regeneration. The catalytic activity is closely related to the contents of pyridinic nitrogen and quaternary nitrogen.


2021 ◽  
Author(s):  
Davidson C Onwumelu

This study compares the effectiveness of activated carbons from the African Teak/Iroko wood (Milicia excelsia) and coconut shell as adsorbents in Crude Palm Oil (CPO) bleaching. This was done in order to source for local agro-waste substitutes for the imported Fuller’s earth. The materials were activated using analytical grade CaCl2 in 25% solution at a temperature of 109OC in a laboratory hot air oven. The obtained activated carbon samples were subjected to proximate analysis to ascertain their percentage ash, moisture, volatile matter and fixed carbon contents. The CPO to be analysed was degummed, neutralized and further bleached using 2g, 4g, 6g, 8g, 10g, 12g and 14g of the adsorbent samples at a temperature of 130OC after which the obtained oils were analysed and results plotted. It was observed that the bleached oil samples generally had reduced specific gravity, opacity, colour, and free fatty acid (FFA) compared to the CPO. It was also observed that the opacity, colour, and FFA reduced as the adsorbent dosage increased. Conversely, the percentage colour reduction and the percentage FFA reduction increased with adsorbent dosage. Overall, the oil samples bleached by activated carbon from the African Teak/Iroko wood exhibited more desirable properties than the ones bleached by the coconut shell activated carbon.


RSC Advances ◽  
2016 ◽  
Vol 6 (88) ◽  
pp. 85390-85410 ◽  
Author(s):  
Ankur Sarswat ◽  
Dinesh Mohan

Slow pyrolysis coconut shell (CSAC) and magnetic coconut shell (MCSAC) activated carbons were prepared, characterized and used for aqueous 2-nitrophenol (2-NP) removal.


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