Detailed Structural Analyses of KOH Activated Carbon from Waste Coffee Beans

Takahata, Tomokazu; Toda, Ikumi; Ono, Hiroki; Ohshio, Shigeo; Akasaka, Hiroki; Himeno, Syuji; Kokubu, Toshinori; Saitoh, Hidetoshi

doi:10.1143/jjap.48.117001

Cited by 20 publications

(17 citation statements)

References 13 publications

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“…In activated carbon chromium ions adsorption increases from 0.1 to 0.3 g and after that it starts decreasing because the number of availability of the exchangeable binding sites for adsorption decreases (Murugesan et al 2012). Figure 5a-e shows the FTIR spectrum of CMC (Rachtanapun and Rattanapanone 2011; Saputra et al 2014), biopolymeric gel beads (Dewangan et al 2011) and activated carbon (Hesas et al 2013;Takahata et al 2009). The distinct difference is observed between CMC, bio-polymeric gel beads and activated carbon.…”

Section: Effect Of Adsorbent Dosagementioning

confidence: 99%

“…Due to the lack of crystallinity, metal ions could easily penetrate into the gel beads and hence increase in adsorption capacity occurs (Yang et al 2011). The diffraction peak at the position of 2θ = 23° shows the amorphous region of the activated carbon because KOH activation increases the specific surface area of porous carbon materials and decreases the crystallinity of the structure (Takahata et al 2009).…”

Section: Xrd Analysismentioning

confidence: 99%

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Adsorptive removal of chromium(VI) from aqueous solution using binary bio-polymeric beads made from bagasse

et al. 2019

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In this study, bio-polymeric gel beads were made from synthetic and laboratory-made CMC (bagasse). Calcium chloride cross-linked with sodium alginate (Na-Alg) added to CMC displayed great affinity for the removal of hexavalent chromium (Cr(VI)) ions present in an aqueous solution. Activated carbon obtained from bagasse was also used for adsorptive removal of Cr(VI) ions from aqueous solution. The effect of different adsorption parameters such as pH, contact time and adsorbent dosage was studied. Bio-polymeric gel beads and activated carbon were prepared and characterized by SEM, FTIR and XRD. The maximum percentage removal for synthetic and bagasse bio-polymeric gel beads reaches 94.56% and 98.42% values at a pH of 4.0 at 25 °C and for activated carbon 64.79% value at a pH of 6.0 at 25 °C. Higher degree of substitution results in an increase in the percentage removal of Cr(VI) ions due to the increase in the surface area and the binding sites of the adsorbent. Our study suggests that bio-polymeric gel beads made from laboratory-made CMC (bagasse) can be used in a more cost-effective and efficient way for the removal of harmful chromium ions.

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Section: Effect Of Adsorbent Dosagementioning

confidence: 99%

Section: Xrd Analysismentioning

confidence: 99%

Adsorptive removal of chromium(VI) from aqueous solution using binary bio-polymeric beads made from bagasse

et al. 2019

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“…Furthermore, the hydrogen storage mechanism should involve physical adsorption to enable repeated use of hydrogen storage equipment. High specific surface areas are required for high-efficiency physical adsorption of hydrogen [2]. Light weight is also necessary for these storage materials to ensure low energy consumption during transport.…”

Section: Introductionmentioning

confidence: 99%

“…Especially, some reports indicated that the activated carbon having large specific surface area adsorbed 0.6-1.3 wt.% of hydrogen at room temperature. [2,4]. It is known that porous carbon materials with a high specific surface area can be prepared by chemical activation with metallic compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Various chemical agents for porous carbon material activation have been studied, such as zinc chloride [5], and acid [6,7]. Recently, higher-specific-surface-area porous carbon materials with alkaline activation have attracted attention [2]. Porous carbon materials with specific surface areas have been produced by the reaction between alkali metal and graphite during alkaline activation with alkaline agents.…”

Section: Introductionmentioning

confidence: 99%

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Effect of chemical species in alkali agents on pore structure at activated carbon of rice husks

Ono

Akasaka

Toda

et al. 2011

Trans. Mat. Res. Soc. Japan

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To understand effect of chemical reactions of the activation process on pore structures, the activated carbon materials were fabricated by two types of chemical agent for the activation process from rice husk ashes. NaOH and Na 2 CO 3 were used as a chemical agent. And their pore structure and hydrogen storage ability were estimated on temperature range from 77 to 298 K. The porous carbon activated by NaOH involved pores of 0.6, 1.1 and 1.5 nm diameter. The pore sizes in porous carbon activated by Na 2 CO 3 were 0.6 and 1.5 nm in diameter. These results indicated that pore structures could be controlled by chemical agents on the activation. The hydrogen storage ability of the porous carbon material activated by NaOH was the same as that activated by Na 2 CO 3 and the value was about 0.5 wt.% at 298 K. With a decrease in temperature, hydrogen storage ability was increased, and the difference of the maximum amount of stored hydrogen on these two porous carbon materials was made larger. The hydrogen storage ability at 77 K porous carbons activated by NaOH and Na 2 CO 3 indicated 3.7 and that for Na 2 CO 3 was 2.1 wt.%. From pore size distributions and temperature dependence, it was suggested that the size of pore for the hydrogen storage changed from 0.6 nm to both 0.6 and 1.1 nm with decreasing temperature.

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Electrochemical Activated Nitrogen‐doped Carbon as Highly Efficient Electrocatalysts for Hydrogen Evolution Reactions

Liang

et al. 2022

ChemNanoMat

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Nitrogen-doped carbon materials play an important role in the electrolysis of water due to their low cost and high stability. The major roles of N-doped carbon materials in water electrolysis are electrocatalysts or catalyst support for metal-based catalysts. However, the evolution of structures and performances of N-doped carbon catalysts/support during electrochemical hydrogen evolution reactions (HER) process has been seldom reported. Here, we found that the catalytic activities of N-doped carbon were electrochemically activated during the in-situ HER process. After electrochemical activation, the catalytic activities of the nitrogen-doped carbon towards HER were drastically improved and even approached the state-of-the-art Pt/C catalyst. The examination of activation conditions and correlation with the catalytical performances demonstrated that the emerged pyridine N-oxide structure was responsible for the enhanced catalytic performances. The reconstruction of surface chemical structures near the active sites during activation results in the enhanced surface hydrophilicity, which in turn makes the active sites more accessible by the protons. As a result, the catalytic HER performances were drastically improved in the activated catalysts.

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Detailed Structural Analyses of KOH Activated Carbon from Waste Coffee Beans

Cited by 20 publications

References 13 publications

Adsorptive removal of chromium(VI) from aqueous solution using binary bio-polymeric beads made from bagasse

Adsorptive removal of chromium(VI) from aqueous solution using binary bio-polymeric beads made from bagasse

Effect of chemical species in alkali agents on pore structure at activated carbon of rice husks

Electrochemical Activated Nitrogen‐doped Carbon as Highly Efficient Electrocatalysts for Hydrogen Evolution Reactions

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