The hydrolysis of cellulose with strong acid results in a product solution containing monosaccharides along with residual acid which must be removed before the sugars can be utilized. Neutralization of this acid would be wasteful but a SMB chromatographic process utilizing the principle of acid retardation on an anion exchange resin can be used to separate a large fraction of the acid and recycle it for further biomass hydrolysis.
A second example of SMB application is in the purification of the byproduct from biodiesel production. The transesterification reaction of triglycerides with methanol produces fatty acid methyl esters (biodiesel) along with a separate phase containing glycerol. Further processing of the glycerol phase yields an aqueous byproduct solution containing glycerol and salts. Chromatographic separation of this solution on a bed of strong cation exchange resin can be used to separate glycerol from most of the salts. For example, with the addition of only eluent water, a solution with a glycerol purity of about 85% (85 g glycerol/100 g dissolved material) can be purified to over 98% glycerol purity in a continuous chromatographic process.