Analysis of SO{sub 2} sorption capacity of rice husk ash (RHA)/CaO/NaOH sorbents using response surface methodology (RSM): untreated and pretreated RHA

Journal Article · Sat Mar 01 00:00:00 EST 2008 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es702232k· OSTI ID:21036888

Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman ^[1]

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1. Universiti Sains Malaysia, Pulau Pinang (Malaysia). School of Chemical Engineering

The SO{sub 2} sorption capacity (SSC) of sorbents prepared from rice husk ash (RHA) with NaOH as additive was studied in a fixed-bed reactor. Rice husk ash is produced by burning rice husks at about 300{sup o}C and was chosen as a source of siliceous material, abundantly available in Malaysia. The sorbents were prepared using a water hydration method by slurrying RHA, CaO, and NaOH. Response surface methodology (RSM) based on four-variable central composite face centered design (CCFCD) was employed in the synthesis of the sorbents. The correlation between the sorbent SSC (as response) with four independent sorbent preparation variables, i.e. hydration period, RHA/CaO ratio, NaOH amount, and drying temperature, were presented as empirical mathematical models. Among all the variables studied, the amount of NaOH used was found to be the most significant variable affecting the SSC of the sorbents prepared. The SSC for sorbent prepared with the addition of NaOH was found to be significantly higher than sorbents prepared without NaOH. This is probably because NaOH is a deliquescent material, and its existence increases the amount of water collected on the surface of the sorbent, a condition required for sorbent-SO{sub 2} reaction to occur at low temperature. The effect of further treatment of RHA at 600{sup o}C was also investigated. Although pretreated RHA sorbents demonstrated higher SSC as compared to untreated RHA sorbents, nevertheless, at optimum conditions, sorbents prepared from untreated RHA was found to be more favorable due to practical and economic concerns. 33 refs., 3 figs., 1 tab.

• OSTI ID: 21036888
• Journal Information: Environmental Science and Technology, Vol. 42, Issue 5; Other Information: [e-mail]; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
09 BIOMASS FUELS
RICE
ASHES
ORGANIC WASTES
SORPTION
SORPTIVE PROPERTIES
SULFUR DIOXIDE
SODIUM HYDROXIDES
ADDITIVES
CHEMICAL REACTORS
ADSORBENTS
CHEMICAL PREPARATION
MATHEMATICAL MODELS
SYNTHESIS
PARAMETRIC ANALYSIS
OPTIMIZATION
DESULFURIZATION
FLUE GAS
WASTE PRODUCT UTILIZATION
MALAYSIA
SURFACES
MORPHOLOGY
SILICA
DISSOLUTION
HYDRATION
PACKED BEDS