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An Alternative Activated Carbon from Agricultural Waste on Chromium Removal

Mahmudi Mohammad, Arsad Sulastri, Amelia Mega Charisma, Rohmaningsih Hajar Alviyyah, Prasetiya Fiddy Semba

Journal of Ecological Engineering

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2020

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Vol. 21, nr 8

1--9

EN

Corn cobs and bagasse are materials used for making activated carbon that are easy to find. Additionally, they are agricultural waste that cannot be consumed. This study aims to analyze the potential of activated carbon from agricultural waste, namely corn cobs and bagasse, in reducing the levels of chromium heavy metal, and to analyze the dose of activated carbon from agricultural waste which is effective in reducing the chromium levels in the batik waste. The method used was experimental with a completely randomized factorial design. The doses of activated carbon used were 0.5, 1.5, and 2.5 g. Meanwhile, the contact times used were 30, 60, 90, 120, and 150 minutes. The results showed that the initial chromium content was 0.144 mg•L-1, and after given treatment it decreased to below 0.024 mg•L-1. The activated carbon from corn cobs and bagasse was able to reduce the chromium levels with the most effective dose of 2.5 g•L-1 and a contact time of 120 minutes. Meanwhile, the water quality parameters showed temperature stability (23–25°C) during the experimental period, while the pH increased to 9–11.

2

Efficiency of corn and poplar biomass saccharification after pretreatment with potassium hydroxide

Dąbkowska-Susfał Katarzyna

Ecological Chemistry and Engineering. S

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2020

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Vol. 27, nr 1

41--53

EN

Pretreatment is an essential step in the conversion of lignocellulosic biomass into valuable products. It aims to increase the biomass susceptibility to enzymatic saccharification to generate fermentable monosaccharides. In this study, the efficiency of 2 % potassium hydroxide (KOH) solution used as a pretreating agent for various lignocellulosic feedstocks, such as corn straw, corncob, and poplar wood, was evaluated. The influence of the pretreatment time, which varied from 0.5 to 24 h at 50 °C, on the alteration of biomass composition was investigated, as well as the enzymatic digestibility. Finally, the overall sugar yields were determined. For corncob, the yield on average amounted to 453.9 ±18.9 mg·g–1 raw (untreated) biomass, regardless of the pretreatment time. The overall sugar yield for both the corn straw and poplar wood biomass increased with increased pretreatment time and ranged from 333.0 to 438.4 mg·g–1 raw biomass and from 123.2 to 215.7 mg·g–1 raw biomass, respectively. Based on the results obtained, the most appropriate pretreatment times for all types of biomass were proposed. The results of this study may be useful for the development of lignocellulosic biomass processing technology.

3

Leaching of manganese ores using corncob as reductant in H2SO4 solution

Ali S., Iqbal Y., Farooq U., Ahmad S.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

56--65

EN

In this study, corncob was used as reductant for sulfuric acid leaching of manganese ore from Daweezi, Upper Mohmand Agency, Pakistan. X-ray diffraction of representative powdered samples revealed the presence of manganese silicate MnSiO(SiO4), calcite (CaCO3), and -quartz (SiO2). X-ray diffraction and energy dispersive spectroscopy analyses indicated that the examined manganese ore was siliceous in nature. Three process parameters were investigated in the present study including the particle size of the ore, leaching temperature, and amount of corncob. Manganese extraction of 92.48 wt% was achieved for a leaching time of 60 min at 90 oC using 1.9 mol/dm3 H2SO4 concentration and 4 g of corncob. The present results demonstrated that corncob is a low cost, renewable, and non-hazardous reducing agent for manganese leaching under mild acid conditions in comparison to the other available reagents.