Specific Surface Area of Nanopowders from Argon Adsorption at 77 and 87 K: Zeta Adsorption Isotherm Approach

Author(s):  
Nagarajan Narayanaswamy ◽  
C. A. Ward
2020 ◽  
Vol 20 (10) ◽  
pp. 6222-6234 ◽  
Author(s):  
Raghubeer S. Bangari ◽  
Niraj Sinha

In this study, we report the synthesis and characterization of boron nitride nanosheets (BNNSs), and their application as an adsorbent to remove the cationic dyes methylene blue (MB) and rhodamine B (RhB) from contaminated water. The synthesized adsorbent was characterized by high-resolution transmission electron microscopy (HR-TEM), field emission electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR) and nitrogen adsorption–desorption isotherm. Detailed experiments and analysis were performed on various molar ratios of boron and nitrogen precursors (1:5 to 1:48) to achieve maximize specific surface area of BNNSs. Among all, the samples synthesized with boric acid and urea (1:30) dissolved in water and methanol produced maximum specific surface area (1801.9 m2 g−1). Further, the adsorption study was performed in batches by investigating various adsorption parameters such as effect of pH, contact time, adsorbent dose and adsorption isotherm. The pH study revealed that optimum value was found to be at pH 8. It was found through the kinetic study that pseudo-second-order (PSO) kinetic model was followed by the adsorbent during the adsorption of both the dyes. Further, the adsorption isotherm data well fitted with Langmuir isotherm model. The maximum adsorption capacities of MB and RhB were found to be 333.33 and 312.5 mg g−1, respectively. This demonstrates the potential of BNNSs as novel adsorbent for treatment of dye-contaminated water.


Author(s):  
Noureddine Elboughdiri ◽  
Babar Azeem ◽  
Djamel Ghernaout ◽  
Saad Ghareba ◽  
Karim Kriaa

Abstract This research study encompasses the utilization of new adsorbents fabricated from pine sawdust for the adsorption of heavy metals and phenol from simulated industrial wastewater. Batch trials are conducted to evaluate the activity of these adsorbents for a possible substitution of the costly commercial adsorbents. The maximum adsorption capacities are evaluated and linked to the physicochemical characteristics of the adsorbents. The maximum monolayer adsorption capacity (qmax) of the adsorbents corresponds to the specific surface area of the adsorbents. The adsorbents with the larger specific surface area have shown higher qmax estimates (phenol adsorption is an exception). The highest amount of the phenol pollutant adsorbed by steam-activated sawdust (SAS) is 10.0 mg/g. The performance of SAS is found to be of the same order as the commercial activated carbon for the removal of Pb and Zn. Equilibrium data for the metal removal are in concordance with the Freundlich adsorption isotherm, whereas the phenol elimination has satisfied the Langmuir adsorption isotherm model. Kinetic data are fitted to Lagergren pseudo-first-order, pseudo-second-order, and the intraparticle diffusion models. Thus, kinetic parameters, rate constants, equilibrium adsorption capacities, and related correlation coefficients for each kinetic model are determined and discussed. The results suggest that the adsorption of Cr follows pseudo-second-order kinetics, indicating chemisorption for the tested adsorbents such that the intraparticle diffusion is not the only step that controls the overall process for Cr adsorption. At the end of this study, the production cost of the SAS adsorbent is estimated ($52 per kg) and compared to the cost of the commercial AC adsorbent in the industrial sector which has a great variation ($80–300 per kg) based on size and location plant. The results of this study can be used for the design of a suitable ecological control procedure to mitigate the harmful effects of industrial wastewater.


2017 ◽  
Vol 68 (3) ◽  
pp. 483-486
Author(s):  
Constantin Sorin Ion ◽  
Mihaela Bombos ◽  
Gabriel Vasilievici ◽  
Dorin Bombos

Desulfurisation of atmospheric distillation gasoline and gas oil was performed by adsorption process on Fe/ bentonite. The adsorbent was characterized by determining the adsorption isotherms, specific surface area, pore volume and average pore diameter. Adsorption experiments of atmospheric distillation gasoline and gas oil were performed in continuous system at 280�320oC, 5 atm and volume hourly space velocities of 1�2 h-1. The efficiency of adsorption on Fe / bentonite was better at desulphurisation of gasoline versus gas oil.


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