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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.

An inorganic sludge from construction and demolition wastes (ICDW) was grafted with APTES to obtain an inorganic-organic modified adsorbent ICDW-APTES. This adsorbent was successfully employed for ciprofloxacin (CFX) adsorption and treatment of synthetic hospital effluent. The chemical composition of ICDW presented large quantities of SiO2and Al2O3,which supports its application for being functionalized by APTES that occurred through a chemical reaction between the surface oxygen groups of oxides with the silanol groups of the APTES. The characterization data suggested that APTES was successfully grafted on the ICDW structure. The kinetic studies showed that the general-order provided the best fitness for CFX adsorption on ICDW-APTES. Liu isotherm model presented the best fitness for the equilibrium studies, and it provided a Qmaxof 138.0 mg g−1at 40.0 °C. Electrostatic interaction was the primary mechanism involved in the adsorption process. The ICDW-APTES also exhibited a good percentage of removal of the two synthetic effluents (71.0 % and 69.0 %).