Brewer's spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer's spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer's spent grain. Activated carbon yields from 16.1 to 23.6 wt.% with high N-contents (> 2 wt.%) were obtained. The efficiency of the prepared activated carbons for phenol adsorption was studied as a function of different parameters: pH, contact time and carbon dosage relative to two commercial activated carbons. The equilibrium isotherms were described by the non-linear Langmuir and Freundlich models, and the kinetic results were fitted using the pseudo-first-order model and the pseudo-second-order model. The feasibility of an activated carbon production facility (onsite and offsite) that processes brewer's spent grain for different input feeds is evaluated based on a techno-economic model for estimating the net present value. Even though the model assumptions start from a rather pessimistic scenario, encouraging results for a profitable production of activated carbon using brewer's spent grain are obtained.

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The optimal conditions to remove radiocesium from water by adsorption on activated carbon (AC) were investigated. Two commercial ACs were compared to ACs prepared by steam activation of brewers' spent grain. The influence of pH and loading AC with Prussian Blue were studied. 134 Cs, measured by gamma-ray spectroscopy, served as a tracer for the Cs concentration. Column experiments showed that a neutral to acidic pH enhanced adsorption compared to high pH. Norit GAC 1240 had the highest adsorption capacity, 8.5 µg Cs g-1 AC for a column filtration. Sequential columns of Norit GAC 1240 removed 28.1 ± 2.8 % of Cs per column.