Original Article
High-Yield Production of Levulinic Acid from Pretreated Cow Dung in Dilute Acid Aqueous Solution
Abstract
biomass; agricultural residue; value-added chemical; glucose; levulinic acid; biorefinery
1. Introduction
Scheme 1. Reaction pathway for the acid-catalyzed conversion of cellulose to levulinic acid.
2. Results and Discussion
2.1. Morphology Change of Cow Dung before and after Pretreatment

Figure 1. SEM image of (a) crude cow dung and (b) pretreated cow dung.
2.2. Catalytic Production of Levulinic Acid from Pretreated Cow Dung by Different Liquid Acids

Figure 2. Production of LA from pretreated cow dung catalyzed by different liquid acid catalysts (reaction conditions: 0.3 g pretreated cow dung, acid aqueous solution 10 mL, 180 °C).
2.3. Catalytic Production of LA from Crude and Pretreated Cow Dung in HCl Aqueous Solutions

Figure 3. Catalytic production of LA from cow dung with and without pretreatment in HCl aqueous solutions (reaction conditions: 0.3 g substrate, 0.2 M HCl aqueous solution 10 mL, 180 °C).
2.4. Effect of the Reaction Temperature on the Production of LA from Pretreated Cow Dung

Figure 4. Effect of reaction temperature on the production of (a) glucose and (b) LA from cow dung. (reaction conditions: 0.3 g pretreated cow dung, 0.4 M HCl aqueous solution 10 mL).
2.5. Effect of Loading Substrate Amount on the Production of LA from Cow Dung

Figure 5. Effect of substrate loading amount on LA production from cow dung (reaction conditions: 0.4 M HCl aqueous solution 10 mL, 180 °C).
2.6. Effect of Acid Concentration on the Production of LA from Cow Dung

Figure 6. Effect of the acid concentration in HCl aqueous solutions on the production of (a) LA and (b) formic acid (reaction conditions: 0.3 g pretreated cow dung, HCl aqueous solution 10 mL, 180 °C).