Upcycling spent brewery grains through the production of carbon adsorbents-application to the removal of carbamazepine from water.

Andreia F C Sousa,María Victoria Gil,Vânia Calisto

doi:10.1007/s11356-020-09543-0

Andreia F C Sousa, María Victoria Gil + Show 1 more

Open Access

https://doi.org/10.1007/s11356-020-09543-0

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Abstract

Spent brewery grains, a by-product of the brewing process, were used as precursor of biochars and activated carbons to be applied to the removal of pharmaceuticals from water. Biochars were obtained by pyrolysis of the raw materials, while activated carbons were produced by adding a previous chemical activation step. The influence of using different precursors (from distinct fermentation processes), activating agents (potassium hydroxide, sodium hydroxide, and phosphoric acid), pyrolysis temperatures, and residence times was assessed. The adsorbents were physicochemically characterized and applied to the removal of the antiepileptic carbamazepine from water. Potassium hydroxide activation produced the materials with the most promising properties and adsorptive removals, with specific surface areas up to 1120 m2 g-1 and maximum adsorption capacities up to 190 ± 27 mg g-1 in ultrapure water. The adsorption capacity suffered a reduction of < 70% in wastewater, allowing to evaluate the impact of realistic matrices on the efficiency of the materials.

Highlights

The use of agricultural and industrial wastes to produce added-value materials is an interesting possibility to reduce the negative impacts of agro-industrial processes, and to reintroduce end-of-life residues into the productive chain (Borel et al, 2018; Jaria et al, 2019)
Spent brewery grains (SBG) are lignocellulosic wastes which constitute a major by-product of the brewing process, representing around 85% of the total wastes generated by the brewing industry (Borel et al, 2018; Vanreppelen et al, 2014)
The washing step was an inevitable cause for material losses, due to the removal of the inorganic fraction

Summary

Introduction

The use of agricultural and industrial wastes to produce added-value materials is an interesting possibility to reduce the negative impacts of agro-industrial processes, and to reintroduce end-of-life residues into the productive chain (Borel et al, 2018; Jaria et al, 2019). The key properties associated to an AC with high adsorption capacities include high specific surface area (SBET) and microporosity, as well as high carbon and low ash contents (Jaria et al, 2015) For these reasons, agro-industrial lignocellulosic residues, which have low inorganic and relatively high volatile contents, are considered good precursors of AC (Azargohar and Dalai, 2008). Spent brewery grains (SBG) are lignocellulosic wastes which constitute a major by-product of the brewing process, representing around 85% of the total wastes generated by the brewing industry (Borel et al, 2018; Vanreppelen et al, 2014) This material consists of the remains from the barley malt after the mashing process (Barrozo et al, 2019), and their properties depend on the type of used barley and the brewing technology (Olszewski et al, 2019). SBG has primarily been used as animal feed (Gonçalves et al, 2017; Vanreppelen et al, 2014)

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