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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Cadmium,Adsorption, Statistical physics modeling, Multi-layer model with saturation
- چکیده:
- چکیده انگلیسی: The adsorption ability of activated carbon, chitosan, and chitosan/activated carbon composite for cadmium separation from aqueous solution was analyzed via statistical physical modeling. The equilibrium data were analyzed by Langmuir, Hill, double layer model, and the multi-layer model with saturation isotherm models. Results showed that the multi-layer model with saturation could well describe the data. The number of the adsorbate ions per site, the receiver site density, the number of formed layers, and the energies of adsorption relative to the different layers were estimated by numerical simulation. Results showed that the chitosan/activated carbon has higher receiver site density and the total amount of adsorbed ions than that other two adsorbents. Results showed that the cadmium adsorption onto activated carbon/chitosan composite is a monolayer and exothermic process. With increasing temperature, the amount of cadmium adsorption decreases due to the fact that the number of receiver adsorption sites decreases. Also, the statistical physics modeling indicated the geometry of cadmium ions adsorbed onto the adsorbent surface is parallel.
- انتشار مقاله: 17-08-1396
- نویسندگان: Hakimeh Sharififard,Hakimeh Sharififard,Hakimeh Sharififard
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Adsorption,Activated charcoal,Palm kernel waste,Xylene
- چکیده:
- چکیده انگلیسی: Xylene is an aromatic hydrocarbon that is a highly toxic compound. Therefore, it is essential to remove this component from wastewater before discharging it to the environment. In this research work, palm kernel biomass was activated chemically by H3PO4 and synthesized activated charcoal was applied to separate xylene from aqueous media. The prepared activated charcoal was characterized using FTIR, BET, SEM, pHzpc measurement, Boehm analysis methods. The characterization tests indicated that the produced activated carbon has acidic character with various functional groups and micropores structure. The values of external mass transfer coefficients ranged from 1.87×10-5 to 1.90×10-5. By increasing the temperature, the pore and surface diffusion coefficients were increased from 1.15×10-9 to 1.91×10-9 and 6.98×10-16 to 7.58×10-16, respectively. Sensitivity analysis indicated which the pore diffusion and film diffusion are the main mass transfer parameters. Equilibrium analysis also revealed that the multilayer model with saturation could well describe the data. The number of adsorbate ions for one site, the number of adsorption layers, density of receptor site, and the energy of adsorption at layers were determined using statistical physics modelling. The maximum capacity of prepared activated charcoal at the experimental condition for xylene adsorption was 23.48 mg g-1.
- انتشار مقاله: 01-04-1397
- نویسندگان: Hakimeh Sharififard,Asghar Lashanizadegan,Rahman Pazira,Parviz Darvishi
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Environmental Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Chitosan,Composite,activated carbon,Chromium,Cadmium
- چکیده:
- چکیده انگلیسی: The aim of this study was to evaluate the adsorption capacity of the novel coated activated carbon by chitosan for removal of Cr (VI) and Cd (II) ions from single and bi-solute dilute aqueous solutions. In addition, the adsorption abilities of activated carbon (AC), chitosan (CH) and chitosan / activated carbon composite (CHAC) have been compared. Adsorption studies were performed in a batch system, and the effects of various operating parameters such as solution pH, particle size and the dose of adsorbent were considered for removal of Cr (VI) and Cd (II) by Taguchi method. Equilibrium experimental data were well fitted to Langmuir isotherm for single and bi-solute solutions. The adsorption capacities of AC and CH adsorbents have improved by synthesis CHAC composite. As it was expected, competitive adsorption of metal ions on the CHAC surface led to reducing the adsorption capacity from 90.9 mg g-1 to 41.94 mg g-1 for Cr (VI) and 52.63 mg g-1 to 30.21 mg g-1 for Cd (II) ions, respectively. The adsorption capacities for the metal solution–adsorbent systems are in the order Cr (VI) > Cd (II). The kinetic studies indicated that the adsorption process was best described by the pseudo-second-order kinetics for single and bi-solute solutions.
- انتشار مقاله: 29-11-1395
- نویسندگان: Hakimeh Sharififard,Mahboubeh Nabavinia,Mansooreh Soleimani
- مشاهده