Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio

Nurgul Ozbay,Adife Seyda Yargic

doi:10.1155/2016/8236238

Abstract

Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C). The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.%) on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW), and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG), Fourier transform-infrared (FT-IR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, point of zero charge measurements (pHPZC), particle size analyzer, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g) was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.

Highlights

Activated carbons (ACs) are materials generally composed of carbon which exhibit well-developed internal surface area and porosity [1]; they have been widely used in different areas such as in gas storage or separation, catalysts and catalyst support, pollutant or odor removal, supercapacitors, pharmaceuticals, and wastewater treatment [2, 3]
KOH, K2CO3, and HCl have been used as activators for preparation of activated carbon from tomato paste waste
Due to the experimental results, characteristics of activated carbons are affected by chemical agents and impregnation ratios

Summary

Introduction

Activated carbons (ACs) are materials generally composed of carbon which exhibit well-developed internal surface area and porosity [1]; they have been widely used in different areas such as in gas storage or separation, catalysts and catalyst support, pollutant or odor removal, supercapacitors, pharmaceuticals, and wastewater treatment [2, 3]. ACs are low-toxic, inexpensive in production, and utilized which can be produced from any natural or synthetic carbonaceous solid precursor such as coal, wood, sawdust, local waste products, and synthetic polymers [4, 5]. Due to the advantages of environmental protection, agricultural or industrial wastes are considered to be critical precursor as they are inexpensive, renewable, safe, available at large quantities, and accessible sources [5]. The production of ACs can be performed by a two-step process: carbonization and activation. The second step is the activation of the material obtained from carbonization step by chemical or physical processes [1, 6]. The physical activation of the char is accomplished in tahgeenptrse,soenr cseteoafmacatitv7at0i0n–g9a0g0e∘nCts[s3u]c. hCahsemairi,caClOa2c,tiovxaitdioizninigs performed by mixing the precursor with an activating agent such as ZnCl2, H3PO4, FeCl3, H2SO4, K2CO3, NaOH, HCl, or KOH [1, 5, 6].Chemical activation has several advantages

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