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

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.

Insights into the Roles of Surface Functional Groups and Micropores in the Sorption of Ofloxacin on Banana Pseudo-Stem Biochars

“…Thus, the contribution of cation exchange to the differential sorption behaviors of OFL on the investigated sorbents could be minimal because OFL + only accounted for 3.83-6.21% of overall OFL concentrations in the sorption systems. Moreover, the phenomenon of H + releasing after OFL sorption as indicated in Equation (7) was not observed in any batch sorption system of the current study, again confirming the above speculation.…”

“…Biochars are carbon-rich solid particles generated from the incomplete combustion of the biomass under an oxygen-limited atmosphere at relatively low temperatures (<700 • C) [5][6][7]. The production of biochar itself is a carbon-negative process because it converts labile biomass into recalcitrant carbon that may persist in the environment for centuries [8]; moreover, the addition of biochar to soil also can mitigate greenhouse emissions.…”

Efficient Adsorption of Tebuconazole in Aqueous Solution by Calcium Modified Water Hyacinth-Based Biochar: Adsorption Kinetics, Mechanism, and Feasibility

“…In addition, the calcium on the biochar was dominated by calcium oxalate. Calcium carbonate was also detected in the modified biochar, which may be due to the decomposition of calcium oxalate at high pyrolysis temperatures [38].…”

Green algae Ulva lactuca-derived biochar-sulfur improves the adsorption of methylene blue from water

“…Additionally, modification methods, including HNO 3 , NaOH, and Na 2 S, have been shown to enhance the adsorption capacity of biochar for Mn(II) removal 35 . Additionally, the excellent adsorption characteristics of cationic dyes have been proven through the use of calcium-rich biochars generated from wasted mushroom substrates, indicating the possibility of particular modifications for targeted adsorption applications 36 .…”