Conventional and Microwave Pyrolysis for Preparation of Sewage Sludge- Activated Carbons for Pharmaceuticals Removal: A Mini-Review

Sewage sludge shows excellent potential as pyrolysis feedstock in generating valuable products such as Activated Carbons (ACs). In this mini-review the preparation of sewage sludge- ACs by two kinds of pyrolysis conventional and microwave heating is presented and discussed. The main difference between conventional pyrolysis and the microwave-assisted method is the way the heat is generated, and both can provide ACs with different textural and chemical properties. Based on what was demonstrated in this work, it is possible to say that both kinds of pyrolysis (microwave and conventional methods) can produce high specific surface area and efficiently activated carbons from sewage sludge. It was also demonstrated that sludge-ACs produced by both pyrolysis methods could reach very high uptakes of pharmaceuticals from aqueous solutions. The van der Waals interactions, hydrogen bonding and π-π interactions of the aromatic ring of the adsorbent with the aromatic rings of the pharmaceuticals have been mentioned to be some of the main mechanisms governing the pharmaceuticals adsorption by ACs.