Co-production of spirosiloxane and biochar adsorbent from wheat straw by a low-cost and environment-friendly method

Wenlong Liu; Xingwen Zhang; Hongyu Ren; Xingcheng Hu; Xinyu Yang; Hui Liu

doi:10.1016/j.jenvman.2023.117851

Co-production of spirosiloxane and biochar adsorbent from wheat straw by a low-cost and environment-friendly method

J Environ Manage. 2023 Jul 15:338:117851. doi: 10.1016/j.jenvman.2023.117851. Epub 2023 Apr 3.

Authors

Wenlong Liu¹, Xingwen Zhang², Hongyu Ren³, Xingcheng Hu⁴, Xinyu Yang⁴, Hui Liu⁵

Affiliations

¹ School of Energy Science and Engineering, Harbin Institute of Technology, No. 92, West Dazhi Street, Harbin, 150001, China; School of Chemistry and Chemical Engineering, Harbin Institute of Technology, No. 92, West Dazhi Street, Harbin, 150001, China.
² School of Chemistry and Chemical Engineering, Harbin Institute of Technology, No. 92, West Dazhi Street, Harbin, 150001, China. Electronic address: zhangxingwen@hit.edu.cn.
³ School of Resources and Environment, Northeast Agricultural University, No. 600, Changjiang Street, Harbin, 150030, China. Electronic address: renhongyu@163.com.
⁴ School of Chemistry and Chemical Engineering, Harbin Institute of Technology, No. 92, West Dazhi Street, Harbin, 150001, China.
⁵ School of Energy Science and Engineering, Harbin Institute of Technology, No. 92, West Dazhi Street, Harbin, 150001, China. Electronic address: liuhui@hit.edu.cn.

PMID: 37019023
DOI: 10.1016/j.jenvman.2023.117851

Abstract

To enhance the value of wheat straw derivatives, wheat straw ash (WSA) was used as a reactant for the first time to synthesize spirocyclic alkoxysilane, an important organosilicon raw material, using an energy-saving and environmentally friendly non-carbon thermal reduction method. After spirocyclic alkoxysilane extraction, the biochar in the wheat straw ash prepared an adsorbent for Cu²⁺. The maximum copper ion adsorption capacity (Q_m) of silica-depleted wheat straw ash (SDWSA) was 31.431nullmg/g, far exceeding those of WSA and similar biomass adsorbents. The effects of the pH, adsorbent dose, and contact time on the adsorption behaviour of the SDWSA for Cu²⁺ adsorption were systematically investigated. The adsorption mechanism of Cu²⁺ by the SDWSA was investigated using the Langmuir, Freundlich, pseudo-first-order kinetic, pseudo-second-order kinetic, and Weber and Morris models by combining the preliminary experimental data and characterization results. The adsorption isotherm and Langmuir equation matched perfectly. The Weber and Morris model can describe the mass-transfer mechanism of Cu²⁺ adsorption by SDWSA. Both film and intraparticle diffusion are rapid control steps. Compared to WSA, SDWSA has a larger specific surface area and a higher content of oxygen-containing functional groups. A large specific surface area provides more adsorption sites. Oxygen-containing functional groups react with Cu²⁺ through electrostatic interactions, surface complexation, and ion exchange, which are the possible adsorption mechanisms for SDWSA. These methods improve the added value of wheat straw derivatives and promote wheat straw ash recovery and centralized treatment. This makes it possible to use the thermal energy of wheat straw and facilitates the treatment of exhaust gases and carbon capture.

Keywords: Adsorption; Biomass; Biosilica; Carbon neutral; Wheat straw.

MeSH terms

Adsorption
Charcoal / chemistry
Hot Temperature
Kinetics
Triticum*
Water Pollutants, Chemical*

Substances

biochar
Charcoal
Water Pollutants, Chemical