Removal of Phenolic Compounds from Olive Mill Wastewater by a Polydimethylsiloxane/oxMWCNTs Porous Nanocomposite

Abstract

User-friendly and energy-efficient methods able to work in noncontinuous mode for in situ purification of olive mill wastewater (OMW) are necessary. Herein we determined the potential of oxidized multiwalled carbon nanotubes entrapped in a microporous polymeric matrix of polydimethylsiloxane in the removal and recovery of phenolic compounds (PCs) from OMW. The fabrication of the nanocomposite materials was straightforward and evidenced good adsorption capacity. The adsorption process is influenced by the pH of the OMW. Thermodynamic parameters evidenced the good affinity of the entrapped nanomaterial towards phenols. Furthermore, the kinetics and adsorption isotherms are studied in detail. The presence of oil inside the OMW can speed up the uptake process in batch adsorption experiments with respect to standard aqueous solutions, suggesting a possible use of the nanocomposite for fast processing of OMW directly in the tank where they are stored. Moreover, the prepared nanocomposite is safe and can be easily handled and disposed of, thus avoiding the presence of specialized personnel. After the adsorption process the surface of the nanomaterial can be easily regenerated by mild treatments with diluted acetic acid, thus permitting both the recyclability of the nanomaterial and the recovery of phenolic compounds for a possible use as additives in food and nutraceutical industries and the recovery of OMW for fertirrigation.

Does Size Matter? The Case of Piezoresistive Properties of Carbon Nanotubes/Elastomer Nanocomposite Synthesized through Mechanochemistry

“…Therefore, to produce spongeous piezoresistive sensors, we used a successful procedure based on a solvent-free mechanochemistry approach [ 20 , 26 , 27 , 28 , 29 ]. This allowed us to avoid the functionalization of the nanomaterials, thus preserving their morphological and electrical properties ( Figure 2 ).…”

Cellulose-Based Hydrogels for Wastewater Treatment: A Focus on Metal Ions Removal

“…Most conventional strategies used for wastewater treatment, such as chemical precipitation, membrane separation, ion exchange, and electrochemical treatments, present limitations which make their scaling up difficult, thus discouraging their application in real contexts in which large water volumes have to be treated, preferably with simple and low-cost procedures based on reusable materials, allowing for reductions in the required time and costs [9][10][11][12][13]. Chemical precipitation, for example, despite being an economical method, requires additional costs for the disposal of the large quantities of sludge produced during the purification process itself [14].…”