Adsorption and separation of black liquor-derived phenol derivatives using anion exchange resins

Kraft black liquor is the major waste stream of the paper pulping industry. This stream is usually directly incinerated in such facilities for energy production and recycling of the inorganic chemicals involved. However, lignin and other low molecular organic fragments dissolved in black liquor give rise to a large variety of aromatic fine chemicals. Energetic use of black liquor and its components prevents the removal of these valuable compounds from the waste stream. We present an easy protocol for adsorption and selective desorption of low molecular phenol derivatives from black liquor depending on the composition of the desorption system. Furthermore, adsorption experiments in model systems provide a rationale for the selectivity of the desorption process. The described process represents a powerful technique for combination of adsorption of low molecular phenols derivatives from alkaline waste streams and online separation of the desired products with respect to their molecular structure.