Biochar production from waste rubber-wood-sawdust and its potential use in C sequestration: Chemical and physical characterization

Published Date

January 2013, Vol.44:18–24, doi:10.1016/j.indcrop.2012.10.017

Title 

Biochar production from waste rubber-wood-sawdust and its potential use in C sequestration: Chemical and physical characterization

• Author 

• Wan Azlina Wan Abdul Karim Ghani ^a,b,,
• Ayaz Mohd ^a,c
• Gabriel da Silva ^b
• Robert T. Bachmann ^d
• Yun H. Taufiq-Yap ^e
• Umer Rashid ^f
• Ala’a H. Al-Muhtaseb ^g,,

• aDepartment of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
• bDepartment of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia
• cSur College of Applied Sciences, P.O. Box 484 Postal Code- 411, Sur - Oman
• dMalaysian Institute of Chemical and Bioengineering Technology (MICET), Universiti Kuala Lumpur, Lot 1988, TabohNaning 78000 Alor Gajah, Malaysia
• eCentre of Excellence for Catalysis Science and Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
• fInstitute of Advanced Technology, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
• gPetroleum and Chemical Engineering Department, Faculty of Engineering, Sultan Qaboos University, P.O. Box 33, Oman

Received 6 August 2012. Revised 13 October 2012. Accepted 15 October 2012. Available online 14 November 2012.

Abstract

Biochars have received increasing attention because of their potential environmental applications such as soil amending and atmospheric C sequestration. In this study, biochar was produced from waste rubber-wood-sawdust. The produced biochars were characterized by Brunauer–Emmett–Teller (BET) gas porosimetry, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). Pyrolysis temperature was shown to have a strong influence on both thermal and chemical characteristic of biochar samples. The experimental data shows that the biochar samples can absorb around 5% water by mass (hydrophilic) at lower temperatures (<550 °C), and that lignin is not converted into a hydrophobic polycyclic aromatic hydrocarbon (PAH) matrix. At higher temperatures (>650 °C), biochar samples were thermally stable and became hydrophobic due to the presence of aromatic compounds. Carbon content (over 85%) increased with increasing temperature, and showed an inverse effect to the elemental ratios of H/C and O/C. The very low H/C and O/C ratios obtained for the biochar indicated that carbon in this material is predominantly unsaturated. BET results showed that the sawdust derived biochars have surface areas between 10 and 200 m² g⁻¹ and FTIR indicated an aromatic functional group about 866 cm⁻¹ in most of the samples. The rate of CO₂ adsorption on sawdust derived biochar generally increased with increasing temperature from 450 to 650 °C but then decreased with increase in the production temperature. Derived biochar represents a potential alternative adsorbent for C sequestration.

Highlights

► Biochar was obtained as byproducts during pyrolysis of waste rubber-wood-sawdust. ► Elemental analysis indicated that carbon in biochar is predominantly unsaturated. ► Pyrolysis temperature strongly influences thermal and chemical characteristics. ► Derived-biochar was found as softwood structure with high surface area of 200 m² g⁻¹. ► Derived-biochar exhibits a CO₂ adsorption capacity of 18 mg/g at 650 °C.

Keywords

• Biochar
• Rubber-wood-sawdust
• Pyrolysis
• Characterization
• C sequestration

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• ⁎ 
  Corresponding author at: Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.

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