Development of Carbon-Based Solid Acid Catalysts Using a Lipid-Extracted Alga, Dunaliella tertiolecta, for Esterification

Abstract

Novel carbon-based solid acid catalysts were synthesized through a sustainable route from lipid-extracted microalgal residue of , for biodiesel production. Two carbon-based solid acid catalysts were prepared by surface modification of bio-char with sulfuric acid (H₂SO₄) and sulfuryl chloride (SO₂Cl₂), respectively. The treated catalysts were characterized and their catalytic activities were evaluated by esterification of oleic acid. The esterification catalytic activity of the SO₂Cl₂-treated bio-char was higher (11.5 mmol Prod.∙h⁻¹∙g Cat. ⁻¹) than that of commercial catalyst silica-supported Nafion SAC-13 (2.3 mmol Prod.∙h⁻¹∙g Cat. ⁻¹) and H₂SO₄-treated bio-char (5.7 mmol Prod.∙h⁻¹∙g Cat. ⁻¹). Reusability of the catalysts was examined. The catalytic activity of the SO₂Cl₂-modified catalyst was sustained from the second run after the initial activity dropped after the first run and kept the same activity until the fifth run. It was higher than that of first-used Nafion. These experimental results demonstrate that catalysts from lipid-extracted algae have great potential for the economic and environment-friendly production of biodiesel.

Tailoring the surface area and the acid–base properties of ZrO2 for biodiesel production from Nannochloropsis sp.

“…Numerous studies have been reported on heterogeneous catalysis for biodiesel production. The most common key features of efficient and active heterogeneous transesterification catalysts are high surface area 9,10 , adequate acidic 11–13 and basic 14–17 densities, good crystallinity 14 , and -well-formed pore structure 10,12,13 . Recent developments in this field have led to renewed interest in bifunctional acid–base heterogeneous catalysts for simultaneous esterification and transesterification of low-grade high-FFA model feedstock 7,18,19 , such as microalgae lipid.…”

Approach to microalgal biodiesel production: Insight review on recent advancements and future outlook

“…synthesized phosphotungstic acid‐modified zeolite as an acid–base active site catalyst for biodiesel from C. vulgaris microalgae oil. Ryu et al 79 . developed a potential carbon‐based solid acid catalyst for biodiesel production from very high FFA content feedstocks such as microalgae lipids.…”

“…Cheng et al 78 synthesized phosphotungstic acid-modified zeolite as an acid-base active site catalyst for biodiesel from C. vulgaris microalgae oil. Ryu et al 79 developed a potential carbon-based solid acid catalyst for biodiesel production from very high FFA content feedstocks such as microalgae lipids. However, heterogeneous acidic catalysts exhibit slow reaction rates; hence, extreme conditions such as high temperature and time with high methanol and catalyst amount are required to achieve high biodiesel yield.…”