A new type of calcium-rich biochars derived from spent mushroom substrates and their efficient adsorption properties for cationic dyes

Haibo Zhang; Long Su; Caiping Cheng; Hongyan Cheng; Mingchang Chang; Fenwu Liu; Na Liu; Kokyo Oh

doi:10.3389/fbioe.2022.1007630

A new type of calcium-rich biochars derived from spent mushroom substrates and their efficient adsorption properties for cationic dyes

Front Bioeng Biotechnol. 2022 Sep 20:10:1007630. doi: 10.3389/fbioe.2022.1007630. eCollection 2022.

Authors

Haibo Zhang^{1

2

3}, Long Su¹, Caiping Cheng⁴, Hongyan Cheng¹, Mingchang Chang^{5

6}, Fenwu Liu^{1

2}, Na Liu¹, Kokyo Oh⁷

Affiliations

¹ College of Resources and Environment, Shanxi Agricultural University, Taigu, China.
² State Key Laboratory of Sustainable Dryland Agriculture (in preparation), Shanxi Agricultural University, Shanxi, Taiyuan, China.
³ Shanxi Key Laboratory of Edible Fungi for Loess Plateau, Taigu, China.
⁴ College of Basic Science, Shanxi Agricultural University, Taigu, China.
⁵ College of Food Science and Engineering, Shanxi Agricultural University, Taigu, China.
⁶ Collaborative Innovation Center of Advancing Quality and Efficiency of Loess Plateau Edible Fungi, Taigu, China.
⁷ Center for Environmental Science in Saitama, Kazo, Japan.

Abstract

Adsorption is commonly accepted as a most promising strategy in dye wastewater treatment, and the widespread use of adsorption emphasizes the need to explore low-cost but excellent adsorbents. Herein, a low-cost adsorbent (calcium-rich biochar) was developed, which was directly pyrolyzed from spent mushroom substate without any modification. This study evaluated the potential application of two calcium-rich biochars (GSBC and LSBC) derived from spent substrates of Ganoderma lucidum and Lentinus edodes, respectively. The effects of pyrolysis temperature on the calcium-rich biochars characteristics and their adsorption mechanism for cationic dyes (Malachite Green oxalate (MG) and Safranine T (ST)) were studied systematically. The increase in pyrolysis temperature from 350 to 750 °C led to an increase in both biochar ash, Ca content, and specific surface area, which made high-temperature biochars (GS750 and LS750) the superior adsorbents for cationic dyes. Batch adsorption results showed LS750 was more efficient to adsorb dyes than GS750 attributed to its higher Ca content and larger specific surface area. According to the Langmuir model, LS750 had high adsorption capacities of 9,388.04 and 3,871.48 mg g^-1 for Malachite green and ST, respectively. The adsorption mechanism of dye MG could be attributed to pore filling, hydrogen bonding, electrostatic interaction, ion exchange, and π-π stacking, while ST adsorption mainly involved pore filling, electrostatic interaction, ion exchange, and π-π stacking. Attributed to their excellent adsorption performance, cheap source, and good reusability, biochars obtained from SMSs were very promising in dyeing wastewater treatment.

Keywords: adsorption mechanism; biochar; calcium; cationic dye; spent mushroom substrate.