Preparation of High-Performance KOH-Activated Biochar from Agricultural Waste ( Sapindus mukorossi ) and Its Application in Organic Dye Removal

Yufeng Zhao, Lu Huang and Guojin Sun ()
Additional contact information
Yufeng Zhao: School of Environmental Science and Engineering, Nanxun Innovation Institute, Zhejiang University of Water Resources and Electric Power, Hangzhou 310018, China
Lu Huang: School of Environmental Science and Engineering, Nanxun Innovation Institute, Zhejiang University of Water Resources and Electric Power, Hangzhou 310018, China
Guojin Sun: School of Environmental Science and Engineering, Nanxun Innovation Institute, Zhejiang University of Water Resources and Electric Power, Hangzhou 310018, China

Sustainability, 2025, vol. 17, issue 19, 1-16

Abstract: The separation of organic dyes from wastewater (WW) is a major challenge in water pollution control. The present research utilised agricultural residuals from Sapindus mukorossi were utilised to prepare high-performance biochar through carbonization and KOH activation, while its efficiency was evaluated in removing methylene blue (MB). The physicochemical characteristics of the unactivated Sapindus shell biochar (SH0) and activated Sapindus shell biochar (SH2) material were characterised via EA, FTIR, BET, and SEM analyses. The findings indicated that the KOH activated Sapindus shell biochar (SH2) exhibited higher adsorption efficiency in comparison to Sapindus shell biochar (SH0). In particular, the SH2 demonstrated an 11.2-fold higher adsorption capacity for MB (502.11 mg·g −1 ) compared to SH0, a performance enhancement driven by its remarkably porous structure, substantial total pore volume (0.56 cm 3 ·g −1 ), and high specific surface area (871.04 m 2 ·g −1 ). A high MB removal efficiency of 98.36% was achieved within 30 min under the following optimal conditions: a KOH/SH0 activation ratio of 2:1, pH 6.5, and a biochar dose of 0.2 g·L −1 . The MB adsorptive process was studied by applying the Langmuir isotherm and PSO kinetic models, suggesting physical and chemical interaction mechanisms between MB dyes and SH2. These findings provide a feasible strategy for the application of Sapindus shells and offer technical support for effectively removing dyes from wastewater by KOH-modified biochar.

Keywords: Sapindus shell biochar; KOH modification; methylene blue dyes; adsorption process (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/17/19/8674/pdf (application/pdf)
https://www.mdpi.com/2071-1050/17/19/8674/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:17:y:2025:i:19:p:8674-:d:1759155

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().