POTASSIUM CARBONATE-TREATED PALM KERNEL SHELL ADSORBENT FOR CONGO RED REMOVAL FROM WATER

2015 ◽  
Vol 75 (1) ◽  
Author(s):  
Lee Lin Zhi ◽  
Muhammad Abbas Ahmad Zaini

This work was aimed to evaluate the adsorptive characteristics of potassium carbonate-treated palm kernel shell adsorbent for the removal of congo red from water. The adsorbent was characterized according to the specific surface area, surface morphology and surface functional groups. The bottle-point technique was employed to investigate the equilibrium uptake and the adsorption kinetics of congo red, and the removal mechanisms were proposed from the widely used isotherm and kinetics models. Results show that the specific surface area of adsorbent increased after the treatment rendering the maximum congo red uptake of 8.0 mg/g. The removal of congo red obeyed Langmuir isotherm and pseudo-second-order kinetics model suggesting the chemically-attributed homogeneous adsorption. Regeneration of congo red-loaded adsorbent by irradiated water showed a better regeneration efficiency of 82%. Palm kernel shell is a promising adsorbent candidate for congo red removal from water.

2017 ◽  
Vol 4 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Norulaina Aliasa ◽  
Muhammad Abbas Ahmad Zaini ◽  
Mohd. Johari Kamaruddin

The present work was aimed to evaluate the effectiveness of two activating agents, namely potassium carbonate (K2CO3) and sodium hydroxide (NaOH) in the chemical activation of palm kernel shell (PKS). The adsorbents were prepared by dried impregnation at different solid mass ratios of activating agent to precursor, followed by thermal treatment at 500°C for 2 h. The adsorbents were characterized for specific surface area, carbon content, ash content and surface functional groups. Results show that the specific surface of K2CO3-activated samples are in the range of 5.3 to 53 m2/g, while that of NaOH-activated samples are between 145 and 458 m2/g. The removal of methylene blue is in accordance with the development of surface area of adsorbents, with the maximum capacity between 7.8 and 69 mg/g, and fitted well with the Langmuir isotherm. The findings conclude that, under the thermal conditions studied, NaOH is better than K2CO3 in the chemical activation of PKS.


2020 ◽  
Vol 17 (2) ◽  
pp. 45
Author(s):  
Sylbialin Amin ◽  
Robert Thomas Bachmann ◽  
Soon Kong Yong

Oil palm plantations produce palm kernel shell (PKS) that can be converted into biochar for environment-friendly soil remediation and water treatment. Oxidation with hydrogen peroxide (H2O2) may enhance surface characteristics and the quality of low-rank PKS biochar as a sorbent for environmental decontamination. This study aims to determine the effect of oxidation on the surface characteristics (i.e., specific surface area, surface charge, and chemical properties) of PKS biochar, and compared with that of PKS activated carbon. The surface area for the oxidised PKS biochar was similar to that of PKS biochar, indicating that oxidation did not remove the pore blocking material from the surface area of the PKS biochar. However, oxidation has increased the amount of negatively charged oxygen functional groups in PKS biochar, as indicated by the analyses of the Fourier transform infrared spectroscopy (FTIR) and cation exchange capacity (CEC). The CEC value of raw and activated PKS biochar were similar and 4.6 and 2.6 times lower for PKS biochar and oxidised PKS biochar, respectively. Oxidation caused enlargement of pores on PKS biochar and caused a reduction of specific surface area. More research is required to establish the process conditions to create a greater surface area and sorption capacity.


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.


Author(s):  
Hieр Nguyen Tien

The kinetics of metallic cobalt nanopowder synthesizing by hydrogen reduction from Co(OH)2 nanopowder under isothermal conditions were studied. Co(OH)2 nanopowder was prepared in advance by chemical deposition from aqueous solutions of Co(NO3)2 cobalt nitrate (10 wt.%) and NaOH alkali (10 wt.%) at room temperature, pH = 9 under continuous stirring. The hydrogen reduction of Co(OH)2 nanopowder under isothermal conditions was carried out in a tube furnace in the temperature range from 270 to 310 °C. The crystal structure and composition of powders was studied by X-ray phase analysis. The specific surface area of samples was measured using the BET method by low-temperature nitrogen adsorption. The average particle size of powders was determined by the measured specific surface area. Particles size characteristics and morphology were investigated by transmission and scanning electron microscopes. Kinetic parameters of Co(OH)2 hydrogen reduction under isothermal conditions were calculated using the Gray–Weddington model and Arrhenius equation. It was found that the rate constant of reduction at t = 310 °C is approximately 1.93 times higher than at 270 °C, so the process accelerates by 1.58 times for 40 min of reduction. The activation energy of cobalt nanopowder synthesizing from Co(OH)2 by hydrogen reduction is ~40 kJ/mol, which indicates a mixed reaction mode. It was shown that cobalt nanoparticles obtained by the hydrogen reduction of its hydroxide at 280 °C are aggregates of equiaxed particles up to 100 nm in size where individual particles are connected to several neighboring particles by contact isthmuses.


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.


BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 729-746
Author(s):  
Junhong Zhang ◽  
Zhi-jun He ◽  
Qing Guo ◽  
De-chao Xiao ◽  
Wen-long Zhan

Microwave modification of activated coke is reported as a green and simple route to improve its synergistic desulfurization and denitrification. The results showed that microwave irradiation improved the specific surface area and pore volume, decreased the pore size, and activated the surface functional groups of the activated coke. Under the conditions of a microwave power of 500 W and a modification time of 30 min, the specific surface area was increased from 185.9 m2/g to 351.7 m2/g, the pore volume increased from 0.042 m3/g to 0.111 m3/g, and the characteristic peak strengths of C=C and -OH drastically increased. When the reaction temperature was 140 °C and the O2 concentration was 10% (by volume), the desulfurization and denitrification efficiency were maintained at levels greater than 90% and 80% for 30 min and 15 min, respectively. The C-O content increased, and the C=C and -OH content decreased after undergoing desulfurization and denitrification. The desulfurization and denitrification products were primarily sulfate and nitrate. This provides theoretical support for the application of microwave modified active coke in low temperature desulfurization and denitrification.


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.


2021 ◽  
Vol 11 (1) ◽  
pp. 43
Author(s):  
Amal Altallhi ◽  
Salwa Moray ◽  
Seham Shaban ◽  
Sahar Ahmed

<p>Nanocrystalline nickel oxide (NiO) and copper oxide (CuO) have been synthesized in a water-in-oil microemulsion. The as-synthesized samples were characterized by X-ray diffraction (XRD), Electron Spin Resonance (E.S.R.), transmission electron microscopy (T.E.M.), and Specific Surface Area (S.S.A.). The particle size of nickel oxide and copper oxide can be controlled from 10.0 to 21.5 and 12.5 to 25.0 nm, respectively, at a different time of calcination temperature with a fixed proportion of water, surfactant, and oil in the microemulsion. Also, the results showed that the specific surface area (89.96 m<sup>2</sup> g<sup>-1</sup>) and pore diameter (8.11 nm) of the prepared nano NiO are higher than the specific surface area (71.96 m<sup>2</sup> g<sup>-1</sup>) and pore diameter (3.71 nm) of the prepared nano CuO. An adsorption test was carried out to show the efficiency of these prepared NiO and CuO nanoparticles for the Adsorption of T.N.T. in an aqueous solution. The removal efficiencies of both nano NiO and CuO were achieved at 90.06% and 77.0%, respectively.<strong></strong></p><p>Additionally, NiO and CuO nanoparticles were regenerated for five cycles. The Kinetic models of Pseudo first-order and pseudo-second-order were described. The results demonstrated that T.N.T. adsorption on both nano adsorbents follows the pseudo-second-order model.</p>


2016 ◽  
Vol 44 (2) ◽  
pp. 129-133
Author(s):  
Muhammad Abbas Ahmad Zaini ◽  
Mohd Shafiq Mohd Shaid

Abstract This study aimed to investigate the adsorptive ability of activated carbons derived from empty boil palm fruitbunch carbons through metal-chloride activation. The derived activated carbons were characterized in terms of yield, pH, surface functional groups, and specific surface area. Rhodamine B dye was used as a pollutant probe to evaluate the performance of activated carbons. Results show that empty, ZnCl2-activated fruit-bunch carbon exhibits a higher surface area of 866 m2 g-1 and a Rhodamine B removal yield of 105 mg g-1. Activation at the same temperature of 600 °C using the recovered FeCl2 yields an activated carbon with nearly twice the surface area compared to the fresh one. A direct correlation was obtained between the roles of the specific surface area and removal of Rhodamine B. Empty fruit-bunch carbon is a promising adsorbent precursor for colour removal from water.


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