Work

Low-cost biomass ash-based adsorbent for removal of hydrogen sulfide gas

Year: 2025

Type: article

Abstract: • The first extruded adsorbent from rubber wood ash-clay matrix is proposed. • NH 4 HCO 3, as novel pore-forming reagent enhances the adsorbent properties. • Achieved an H 2 S of 3.88 mg /g adsorbent, capacity is competitive to another non-highly activated ash adsorbent. • Optimal formulation: 79 % ash, 2.5 % NH 4 HCO 3 , and 293 °C, yielding chemisorption as the main removal mechanism. This research aims to use boiler-biomass ash to produce low-cost and efficient adsorbent for removing hydrogen sulfide (H 2 S) in biogas from small scale biogas plant. To reduce pressure drop across adsorbent bed during the practical adsorption, clay was selected as a binder to perform the extruded adsorbent. 15 different adsorbents using different proportion of ash to clay (70–90 %) together with the an amount of NH 4 HCO 3 as pore-forming reagent (0–6 %), and baking temperature (100–500 °C) were prepared. From the breakthrough cure studies using fixed-bed column fed by 0.1 L/min synthetic H 2 S containing gas, it was found that quadratic equation with R 2 0.75 can be used to optimize adsorption preparation and predict H 2 S adsorption capacity. The optimized adsorbent prepared using 79 % ash, and 2.5 % NH 4 HCO 3 at 293 °C was validated and had achieved H 2 S adsorption capacity of 3.67–3.88 mg/g. The characterization results, including BET surface area analysis and SEM imaging , show significant pore formation due to the presence of NH 4 HCO 3 . CHNS/O SEM-EDX, and XRF analyses confirmed that there wasan increase in sulfur content of the post-adsorbent. The decrease in surface area and change of functional groups in FTIR spectrum of the spent adsorbent, and presence of metal elements supporting the chemisorption mechanism were also discovered. The best fitted breakthrough curve operated at 200–10,000 ppm H 2 S containing gas to Thomas model which could be implemented for further scaling up are also proposed. This is a successful attempt to use an abundance industrial waste, eco-friendly local material and novel pore forming agent in order to create an eco-efficient adsorbent for H 2 S removal.

Source: Carbon Resources Conversion

DOI: 10.1016/j.crcon.2025.100327

Authors: Kanathip Promnuan, Rusmanee Ma, Marisa Raketh, Prawit Kongjan, Saowapa Chotisuwan, Rattana Jariyaboon

Institutions: Prince of Songkla University, Universitat Rovira i Virgili

Language: English

Topic: Industrial Gas Emission Control

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Responsible consumption and production

Open Access status: gold

Estimated APC paid: $1,100