Use of nanoparticles for dye adsorption: Review

A very serious problem nowadays is the colored waters and especially the wastewaters from dyeing industries. Many techniques were already applied in order to treat those effluents, but one of the most simple, low-cost, effective, and successful is adsorption. A very promising class of materials used for this purpose is nanoparticles. This review summarizes some very important works of the last years regarding the use of nanoparticles as potential adsorbent materials for dye adsorption (mainly wastewaters). Widely-used models are described and analyzed for finding the best theoretical adsorption capacity (Langmuir, Freundlich, etc.), as well as some kinetic (pseudo-first, -second order, etc.), thermodynamic (free energy Gibbs, enthalpy, entropy), and desorption/regeneration studies are also discussed in details. Moreover, significant factors such as pH, agitation time, temperature, adsorbent dosage, and initial dye concentration are also reported extensively. Based on thermodynamic studies, meta-data analysis was carried out and commented.