Papers by Keyword: Chemical Activation

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Authors: Ke Qing Li, Yang Yi Zhang, Peng Zhao, Lin Feng
Abstract: The back-filling method is distinguished from other mining methods by its higher cost. In order to solve this problem and utilize water-granulated nickel slag as much as possible, nickel slag from flash smelting operation was used to prepare cementitious materials for backfilling. Approaches including mechanical activation and chemical activation were adopted to improve the cementitious activity of the slag. By taking the strength of the backfill materials as the evaluation standards, the hydration activity and cementitious performance of the slag were investigated under different activation conditions, and the mechanism of chemical activation was analyzed. The results shows that cementing agent prepared by using mainly the slag (occupying 85% of the total raw materials) can be used to replace cement and meet the production requirements for backfilling materials.
Authors: S. Azat, Rosa Busquets, V.V. Pavlenko, A.R. Kerimkulova, Raymond L.D. Whitby, Z.A. Mansurov
Abstract: This article presents the results of the synthesis of carbon nanomaterials: Nanoscale materials obtained by carbonization of waste agricultural products (apricot kernel, Greek walnut (GW), rice husk). The results of physico-chemical characteristics of the obtained nanomaterials. Physico-chemical parameters of the synthesis of carbonized sorbents based on plant raw material are investigated along with the properties of these sorbents. The data of FTIR, ESR spectroscopy & BET-method, as well as electron microscopy are reported. It is stated that carbonized sorbents possess high specific surface area and porosity. Carboxylic, carbonyl, hydroxyl groups are detected on the surface of the synthesized sorbents. Separate fusicoccine and similar biostimulators effectively; remove LPS-endotoxines from blood plasma selectively. They may be used as carriers to introduce probiotics into intestine thanks to formation of stable colonies on their developed surface. A method of preparation of honeycomb monoliths from carbonized rice husk with developed mesoporous structure via modification of the porous structure by silica leaching has been developed.
Authors: Azry Borhan, Kok Hoong Phoon, Mohd Faisal Taha
Abstract: The objective of this research is to study the potential of using banana peel as a biosorbent in removing heavy metal ions (Cu2+, Zn2+ and Pb2+) and oil/grease particles from industrial waste water. The study emphasizes on the parameters involved in the preparation phase of the banana peel adsorbent, such as particle sizes, activating agent, impregnation ratio, carbonization temperature and duration. Based on the findings, it shows that the adsorption capacity is correlated to the total surface area (SBET), pore volume (VT) and average pore diameter (D) of the materials. Sample A20 yields the highest percentage removal for all tested waste water pollutants, suggesting that banana peel based activated carbon can be used effectively as biosorption material.
Authors: Noor Shawal Nasri, Jibril Mohammed, Muhammad Abbas Ahmad Zaini, Usman Dadum Hamza, Husna Mohd. Zain, Farid Nasir Ani
Abstract: There is significant portion of agricultural wastes in the world posing environmental challenge; however, they could be converted into useful products like activated carbon. In this study, coconut shell based carbons were synthesized using chemical activation with potassium acetate (PAAC), potassium hydroxide (PHAC) and physical activation by CO2 (CSAC). The properties of potassium acetate-activated carbon were characterized and the results were compared with the other activation methods. The pyrolysis temperature of 700°C for 2h yielded 32% of char. The BET surface area and pore volume of PAAC are 622m2/g and 0.31cm3/g; while 369m2/g and 0.19cm3/g, and 1354m2/g and 0.61cm3/g were recorded for CSAC and PHAC, respectively. CSAC yielded lower surface area with approximately 88% micropores. On the other hand, PAAC yielded higher surface area with approximately 50% of both micropores and mesopores, whereby this heteroporous property would suffice for a wider range of application. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes, carbonyls and aromatics functional groups were identified with more prominent peaks on the chemically activated porous carbons. From thermogravimetric analysis (TGA), lignin decomposition occurred in a wider temperature range (390-650°C). The properties of PAAC could offer a sustainable means for treatment of toxic waste streams.
Authors: Azry Borhan, Mohd Faisal Taha, Athirah Amer Hamzah
Abstract: The preparation of activated carbon from wood-based industrys residue is one of the most environmental friendly solutions of transforming negative-valued wastes to valuable materials. Wood sawdust was first chemically activated using potassium hydroxide, KOH and characterized by nitrogen adsorption-desorption isotherms measured in Micrometrices ASAP 2020 and Field Emission Scanning Electron Microscope (FESEM). By manipulating three different parameters, the optimal activation conditions were found at temperature of 500°C, activation time of 60 min and impregnation ratio of 1:3. Results showed that the BET surface area, total pore volume and diameter of activated carbon were 1876.16 m2 g-1, 0.88 cm3 g-1 and 6.93 nm, respectively. Nitrogen adsorption desorption isotherm analysis proved the existence of mesopores in activated carbon produced, suggesting that it can be effectively used as an adsorption material.
Authors: Jonjaua Ranogajec, K. Kasaš, J. Kanazir, A.B. Mesaroš
Authors: Suren L. Kharatyan, Hayk H. Nersisyan
Authors: Jibril Mohammed, Noor Shawal Nasri, Muhammad Abbas Ahmad Zaini, Usman Hamza Dadum, Murtala Musa Ahmed
Abstract: There is significantly abundant portion of waste agricultural materials in the world serving as environmental challenge, however, they could be converted into useful value added products like activated carbon. Coconut shell based carbons were synthesized using physical activation by CO2 and chemical activation with potassium hydroxide and potassium acetate. The BET surface areas and pore volumes are 361m2/g and 0.19cm3/g for physical activation, 1353m2/g and 0.61cm3/g for activation with KOH and 622m2/g and 0.31cm3/g for potassium acetate activated carbon. From the Fourier Transform Infrared Spectroscopy analysis, hydroxyls, alkenes and carbonyl functional groups were identified with more prominence on the chemically activated porous carbons. Thermogravimetric analysis (TGA) results showed occurrence of moisture pyrolysis at 105°C, the pyrolysis of hemicellulose and cellulose occurred at 160–390°C and lignin at (390-650°C). Carbonization at 700°C and 2hrs had highest yield of 32%. Physical activation yielded lower surface area with approximately 88% micropores. On the other hand, chemically activation yielded higher surface area with elevated mesopores. The porous carbons can be applied to salvage pollution challenges.
Authors: Jimoh Abdulfatai, Abdulkareem Ambali Saka, Ayo Samuel Afolabi, Onazi Micheal
Abstract: This study investigated the development and application of banana peel for the remediation of heavy metals (Pb, Zn and Cr). Batch experimental processes as well as conditions that might influence the sorption of the metals were investigated. These conditions include effects of pH, contact time, adsorbent dose, and particle size. The applicability of the sorption process was tested on wastewater. The adsorbent activated with 0.5 M H2SO4 showed the highest percentage removal of chromium ion (88.9 %) at a pH of 6. It has been found that particle size has no effect on the removal of zinc ion and it has also been found that the removal efficiency of lead and chromium ion decreased with increase in contact time and particle size. Also, it can be seen from the results that untreated banana peel waste increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD) values of wastewater. The results from the optimized method revealed the applicability of the method to environmental water samples. This study therefore confirms that banana peel is a promising adsorbent for the removal of chromium from industrial effluent.
Authors: Kamonwan Aup-Ngoen, Mai Noipitak
Abstract: The preparation of carbon materials from low-cost agricultural residues is presented in this work. Carbon products were prepared from carbonized cassava tuber (cassava tuber char, CTC) using a chemical activation assisted sonochemical process incorporating KOH as an activating agent. The physical properties such as proximate analysis, ultimate analysis and FTIR spectra of raw material were studied using cassava tuber collected from farmland in the Kanchanaburi Province. The structure of the precursor material played a significant role in influencing the quality and properties of the as-prepared carbon. It was found that the specific surface area of carbon products was improved through chemical activation assisted sonochemical process at 80 °C for 4 hours. The influence of KOH impregnation ratios on the specific surface area of the prepared carbon was also investigated in the activation step. Moreover, the properties of cassava tuber-carbon material were characterized by SEM, FTIR, XRD, and multipoint BET analysis. Finally, the application of cassava tuber carbon material as a carbon support for ZnO photocatalyst was investigated by a simple technique.
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