scholarly journals Adsorption-desorption study of selected pesticides and a typical dye in different soils and their removal by high cost activated carbons and low cost materials based on statistical response surface methodology

2009 ◽  
Author(s):  
Md. Azharul Islam
2014 ◽  
Vol 1053 ◽  
pp. 303-310 ◽  
Author(s):  
Mian Wu Meng ◽  
Cong Liang Qi ◽  
Qing Ye Liu ◽  
Liang Lv ◽  
Hao Ai ◽  
...  

A three-factor-three-level experiment was developed by the central composite design (CCD) and Response surface methodology to discuss the effects of concentration of K2CO3, activation temperature and time on the adsorption capacity of the activated carbon (AC) derived from the rice husk and to identify the key preparation parameters. The performance of the AC was characterized by nitrogen adsorption isotherm as Brunauer–Emmett–Teller (BET) and scanning electron microscope (SEM), respectively. The optimal parameters were obtained: Rice husk was soaked in K2CO3 solution (2.32 mol/L) with an impregnation ratio (rice husk: K2CO3=1:3) (wt. %), activated at 1239 K for 0.48 h. The results showed that iodine adsorption capacity of the AC was 1268.52 mg/g, the error between the models predicted (1356.98 mg/g) was only 6.2%. The AC has a large apparent surface area (SBET = 1312 m2/g), total pore volume (0.78 cm3/g) and average pore diameter (11.92 Å).


2016 ◽  
Vol 15 (01n02) ◽  
pp. 1650001 ◽  
Author(s):  
A. Tamilvanan ◽  
K. Balamurugan ◽  
K. Ponappa ◽  
B. Madhan Kumar

Electrolysis is a method used for producing copper (Cu) nanoparticles at faster rate and at low cost in ambient conditions. The property of Cu nanoparticles prepared by electrolysis depends on their process parameters. The influence of selected process parameters such as copper sulfate (CuSo4) concentration, electrode gap and electrode potential difference on particle size was investigated. To optimize these parameters response surface methodology (RSM) was used. Cu nanoparticles prepared by electrolysis were characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM). After reviewing the results of analysis of variance (ANOVA), mathematical equation was created and optimized parameters for producing Cu nanoparticles were determined. The results confirm that the average size of Cu particle at the optimum condition was found to be 17[Formula: see text]nm and they are hexagonal in shape.


2020 ◽  
Vol 38 (9-10) ◽  
pp. 450-463
Author(s):  
Xiya Li ◽  
Jieqiong Qiu ◽  
Yiqi Hu ◽  
Xiaoyuan Ren ◽  
Lu He ◽  
...  

The production of low-cost biologically activated carbons (BACs) is urgent need of environmental protection and ecological sustainability. Hence, walnut shells were treated by traditional pyrolysis, direct KOH impregnation and combined activation composed of hydrothermal carbonization and two-step H3PO4- and pyrolysis-activation process to obtain porous carbon with high adsorption capacity. It was found that the best adsorption capacity for iodine and organic dye methylene blue (MB) can be obtained using the KOH impregnation at impregnation ratio of 1:1 or combined activation comprising of 2 h H3PO4 activation and 1 h pyrolysis activation at 1000°C. The produced KOH, H3PO4/pyrolysis activated BACs at the optimum conditions are superior to that of commercial ACs, 9.4 and 1.3 times for MB removal, 4 and 4.5 times for iodine number respectively. Characterization results demonstrated their porous structure with very good textural properties such as high BET surface area (1689.1 m2/g, 1545.3 m2/g) and high total pore volume (0.94 cm3/g, 0.96 cm3/g). The N2 adsorption-desorption isotherm of H3PO4/pyrolysis activated hydrochar suggested the co-existence of micro and meso-pores. Moreover, they are more effective for the removal of Fe(III) and Cr(VI) from aqueous solution than the commercial AC, suggesting a promising application in the field of water treatment.


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