Effect of water washing pretreatment on property and adsorption capacity of macroalgae-derived biochar. (1st March 2019)

• Record Type: Journal Article
• Authors: Boakye, Patrick; Tran, Hai Nguyen; Lee, Dae Sung; Woo, Seung Han
• Is Part Of: Journal of environmental management. Volume 233(2019)
• Page Start: 165
• Page End: 174
• Publication Date: 2019-03-01
• Subjects: Adsorption -- Ash role -- Biochar -- Crystal violet dye -- Saccharina japonica algae -- Water washing pretreatment; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2018.12.031
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The effects of water washing pretreatment process on the property and adsorption capacity of biochar were investigated at different biochar/water ratios from 1:5 to 1:100 (w/v). Saccharina japonica macroalgae-derived biochars (B300, B450, and B600) were prepared at 300 °C, 450 °C, and 600 °C, respectively. The optimal biochar/water ratio was obtained at 1:10. The results indicated that the washing pretreatment can contribute to dramatically increasing the specific surface area of biochars, but slightly increasing their porosity. The washed biochars were carbonaceous microporous materials (67–80% micropore volume), with their specific surface area and porosity being B600 (543 m 2 /g and 86%), B450 (521 m 2 /g and 75%), and B300 (188 m 2 /g and 80%), respectively. The unwashed biochars exhibited a significantly higher ash content (59%–65%) than washed biochars (26%–35%). Equilibrium adsorption study demonstrated that the Langmuir maximum adsorption capacity ( Q o max ) of crystal violet cationic dye decreased in the following order: unwashed-B450 (1719 mg/g) > washed-B450 (1277 mg/g) > commercial activated carbon (492 mg/g). The washing pretreatment can remove solute-inorganic minerals to prevent their release from biochar during the dye adsorption. The washed biochar with its excellent adsorption capacity can serve as a highly sustainable and industrially viable adsorbent for the removal of cationic dyes from waste bodies. Highlights: Biochar from Saccharina japonica -derived sulfated macroalgae at 300, 450, and 600 °C. Washing pretreatment on biochar's property and cationic dye adsorption capacity. S BET -biosorbent (0.03–0.21); chars: unwashed (1.36–266), washed (188–543); CAC (688). Langmuir Q o max : CAC < biosorbent < washed biochars < unwashed biochars. Washing pretreatment prevents minerals release from chars during dye adsorption.