Thesis

Optimisation of brewer’s spent grain biochar synthesis for remediation of emerging contaminants from water

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Awarding institution
  • University of Strathclyde
Date of award
  • 2026
Thesis identifier
  • T17616
Person Identifier (Local)
  • 202075429
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Qualification Name
Department, School or Faculty
Abstract
  • Emerging contaminants are a class of pollutants in water of growing prominence due to their endocrine disrupting properties, persistence in the environment and potential adverse effects on humans and the environment. Adsorbents such as activated carbons and biochars are used in wastewater treatment applications, however new synthesis precursors and pathways are constantly required to develop new functional adsorbents in environmentally and economically sustainable ways. Brewer’s Spent grain has been identified as a precursor material of interest, due to its low cost, homogeneity and high carbon and nitrogen content capable of being upcycled into biochars. However, no systematic optimisation process or full characterization of biochars from brewer’s spent grain has been carried out. Here we show the optimisation of brewer’s spent grain biochar through utilisation of design of experiments and fully characterise the optimal adsorbent composition, textural properties, and adsorption behaviour with the surrogate pollutant methyl orange dye. Through screening design of experiments, we found that hold temperature and hold time were the only factors of statistical significance, but washing with the chemical activating agent hydrochloric acid was required to alter the surface chemistry of the materials. The optimal synthesis conditions for the biochar were at 900°C and a hold time of 2.5 hours giving a yield of 7.6%, a surface area of 1433 m2 g-1, small mesopore and large micropore sizes and a variety of aromatic, oxygen and nitrogen containing functional groups on the surface. Notably, silica present within the feedstock is mobilised to the surface after pyrolysis, presenting another possible site for adsorption. Methyl orange dye adsorption on the surface followed the Temkin isotherm model, indicating heterogenous adsorption behaviour. Thermodynamic studies indicated an initial physisorptive mechanism with enthalpy of -51.9 kJ mol-1 followed by a chemisorptive mechanism after an uptake of approximately 270 mg g-1. These results demonstrate the suitability of brewer’s spent grain biochars for use in water remediation applications, creating a circular economic pathway to upcycle the waste material from the brewing industry. These materials present an environmentally friendly and cost-effective method of biochar production as compared to other non-renewable precursor derived biochars such as those derived from peat and coal. It also presents a local waste route to Scotland as compared to imported biomass waste, further advancing sustainability initiatives.
Advisor / supervisor
  • Fletcher, Ashleigh
Resource Type
DOI
Date Created
  • 2025

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