scholarly journals Bio-polishing sludge adsorbents for dye removal

2016 ◽  
Vol 18 (4) ◽  
pp. 15-21 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Norulaina Alias ◽  
Mohd. Azizi Che Yunus

Abstract The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR) > zinc chloride-treated (SZ) > microwave-dried (SW) = potassium carbonate-treated (SK) > acid-washed (SH). The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.

2018 ◽  
Vol 7 (4) ◽  
pp. 344-352 ◽  
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Raidah Md. Sudi

AbstractThe present study was aimed at evaluating the performance of human hair as adsorbents for methylene blue (MB) dye removal. Human hair was treated using 0.1mpotassium hydroxide (KOH) and 0.1mnitric acid, and the adsorbents were characterized for specific surface area and surface chemistry. The basic-treated human hair adsorbent (BH) exhibits a specific surface area of 3.51 m2/g, which is relatively higher than the acid-treated (AH) and untreated (UH) counterparts. The equilibrium data of all adsorbents obeyed the S-shaped isotherm, suggesting a cooperative adsorption. The BH displays a maximum capacity of 13.5 mg/g, while a comparable capacity of 3.4 mg/g was recorded by AH and UH. The adsorption of MB by BH increased with increasing pH. Based on the equilibrium and kinetics data, the adsorption of MB onto BH is proposed to have the following mechanisms: (i) external diffusion, (ii) intraparticle diffusion, and (iii) cooperative adsorption. In addition, the MB adsorption at a concentration of 20 mg/l is endothermic and spontaneous with temperature increasing from 35°C to 55°C. A basic treatment of human hair using KOH yields a promising adsorbent for dye in wastewater treatment.


2015 ◽  
Vol 74 (7) ◽  
Author(s):  
Nur Haziqah Mohd. Nasir ◽  
Muhammad Abbas Ahmad Zaini ◽  
Siti Hamidah Mohd. Setapar ◽  
Hashim Hassan

This study aims to evaluate the adsorptive properties of oil palm empty fruit bunch for the removal of cationic pollutants in water. The untreated and hydrochloric acid-treated empty fruit bunches were characterized based on pH of adsorbent, specific surface area and surface functional groups. The adsorbents were then used to challenge varying concentrations of methylene blue dye and copper (II) in aqueous solution. Results show that the specific surface area of empty fruit bunch decreased upon the treatment with hydrochloric acid. The untreated adsorbent displays a higher equilibrium removal of the target pollutants due to its higher specific surface area of 28.4 m2/g. The maximum removal were recorded as 0.103 and 0.075 mmol/g for methylene blue and copper (II), respectively. Oil palm empty fruit bunch is a promising candidate for the removal of cationic pollutants in aqueous solution. 


2021 ◽  
Vol 10 (3) ◽  
pp. xx-xx
Author(s):  
Chien Hoang Thi ◽  
Ly Vu Thi Huong ◽  
Thao Tran Thi ◽  
Thuy Vu Thi ◽  
Ngan Nguyen Thi ◽  
...  

For the first time, the expansion grade of graphite was studied through the effect of the flake size. The result shown the larger flake size exhibits a higher expansion grade.  In addition, the more expanded material, the higher specific surface area can be obtained. The synthesized expanded graphites were used for the adsorption of methylene blue. The expanded graphite with the highest expansion grade displayed the highest adsorption capacity due to its specific surface area.


2013 ◽  
Vol 67 (8) ◽  
pp. 1688-1694 ◽  
Author(s):  
Z. Ioannou ◽  
J. Simitzis

Mixtures of novolac resin and olive stone biomass (20/80 and 40/60 w/w) were cured, pyrolyzed up to 1,000 °C and activated with CO2 under a continuous flow operation (named N20B-cCa and N40B-cCa respectively). Commercial activated charcoal was similarly re-activated with CO2 and used for comparison reasons (AC-a). The characterization of these materials was performed by Fourier transform Infrared (FTIR) analysis and their specific surface area was determined according to DIN 66132. The materials were tested for their adsorption abilities at different temperatures (298, 333 K) and initial dye concentrations (0.01–0.35 g/L) using 1 L of methylene blue (MB) solution in 10 g of activated carbon. MB adsorption kinetic was also studied. The FTIR spectra of all activated carbons show absorption peaks which correspond to –OH, –CH, –C–O–C– groups and to aromatic ring. The presence of the absorption peak at about 1,400 cm−1 for N20B-cCa, N40B-cCa indicates more acidic groups on them compared to the commercial AC-a. The specific surface area of N20B-cCa, N40B-cCa and AC-a has values equal to 352, 342 and 760 m2/g respectively. From the applied kinetic models, pseudo-second-order equation could best describe MB adsorption. Consequently, such adsorbents can be used as filters to adsorb dyes from wastewaters.


Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 173
Author(s):  
Velma Beri Kimbi Yaah ◽  
Satu Ojala ◽  
Hamza Khallok ◽  
Tiina Laitinen ◽  
Marcin Selent ◽  
...  

This paper presents results related to the development of a carbon composite intended for water purification. The aim was to develop an adsorbent that could be regenerated using light leading to complete degradation of pollutants and avoiding the secondary pollution caused by regeneration. The composites were prepared by hydrothermal carbonization of palm kernel shells, TiO2, and W followed by activation at 400 °C under N2 flow. To evaluate the regeneration using light, photocatalytic experiments were carried out under UV-A, UV-B, and visible lights. The materials were thoroughly characterized, and their performance was evaluated for diclofenac removal. A maximum of 74% removal was observed with the composite containing TiO2, carbon, and W (HCP25W) under UV-B irradiation and non-adjusted pH (~5). Almost similar results were observed for the material that did not contain tungsten. The best results using visible light were achieved with HCP25W providing 24% removal of diclofenac, demonstrating the effect of W in the composite. Both the composites had significant amounts of oxygen-containing functional groups. The specific surface area of HCP25W was about 3 m2g−1, while for HCP25, it was 160 m2g−1. Increasing the specific surface area using a higher activation temperature (600 °C) adversely affected diclofenac removal due to the loss of the surface functional groups. Regeneration of the composite under UV-B light led to a complete recovery of the adsorption capacity. These results show that TiO2- and W-containing carbon composites are interesting materials for water treatment and they could be regenerated using photocatalysis.


2015 ◽  
Vol 749 ◽  
pp. 17-21 ◽  
Author(s):  
Joanna Sreńscek Nazzal ◽  
Karolina Glonek ◽  
Jacek Młodzik ◽  
Urszula Narkiewicz ◽  
Antoni W. Morawski ◽  
...  

Microporous carbons prepared from commercial activated carbon WG12 by KOH and/or ZnCl2 treatment were examined as adsorbents for CO2 capture. The micropore volume and specific surface area of the resulting carbons varied from 0.52 cm3/g (1374 m2/g) to 0.70 cm3/g (1800 m2/g), respectively. The obtained microporous carbon materials showed high CO2 adsorption capacities at 40 bar pressure reaching 16.4 mmol/g.


2021 ◽  
Vol 15 (2) ◽  
pp. 131-144
Author(s):  
Chunjiang Jin ◽  
Huimin Chen ◽  
Luyuan Wang ◽  
Xingxing Cheng ◽  
Donghai An ◽  
...  

In this study, aspen wood sawdust was used as the raw material, and Fe(NO3)3 and CO2 were used as activators. Activated carbon powder (ACP) was produced by the one-step physicochemical activation method in an open vacuum tube furnace. The effects of different mass ratios of Fe(NO3)3 and aspen wood sawdust on the pore structure of ACP were examined under single-variable experimental conditions. The mass ratio was 0–0.4. The detailed characteristics of ACP were examined by nitrogen adsorption, scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption capacity of ACP was established by simulating volatile organic compounds (VOCs) using ethyl acetate. The results showed that ACP has a good nanostructure with a large pore volume, specific surface area, and surface functional groups. The pore volume and specific surface area of Fe-AC-0.3 were 0.26 cm3/g and 455.36 m2/g, respectively. The activator played an important role in the formation of the pore structure and morphology of ACP. When the mass ratio was 0–0.3, the porosity increased linearly, but when it was higher than 0.3, the porosity decreased. For example, the pore volume and specific surface area of Fe-AC-0.4 reached 0.24 cm3/g and 430.87 m2/g, respectively. ACP presented good VOC adsorption performance. The Fe-AC-0.3 sample, which contained the most micropore structures, presented the best adsorption capacity for ethyl acetate at 712.58 mg/g. Under the action of the specific reaction products nitrogen dioxide (NO2) and oxygen, the surface of modified ACP samples showed different rich C/O/N surface functional groups, including C-H, C=C, C=O, C-O-C, and C-N.


2012 ◽  
Vol 463-464 ◽  
pp. 543-547 ◽  
Author(s):  
Cheng Feng Li ◽  
Xiao Lu Ge ◽  
Shu Guang Liu ◽  
Fei Yu Liu

Core-shell structured hydroxyapatite (HA)/meso-silica was prepared and used as absorbance of methylene blue (MB). HA/meso-silica was synthesized in three steps: preparation of nano-sized HA by wet precipitation method, coating of dense silica and deposition of meso-silica shell on HA. As-received samples were characterized by Fourier transformed infare spectra, small angle X-ray diffraction, nitrogen adsorption-desorption isotherm and transmission electron microscopy. A wormhole framework mesostructure was found for HA/meso-silica. The specific surface area and pore volume were 128 m2•g-1 and 0.36 cm3•g-1, respectively. From the adsorption isotherm, HA/meso-silica with the great specific surface area exhibited a prominent adsorption capacity of MB (134.0 mg/g) in comparison with bare HA (0 mg/g). This study might shed light on surface modification of conventional low-cost adsorbents for removal of organic pollutants from aqueous solutions.


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