Removal of Hazardous Pollutants from Wastewaters: Applications of TiO₂‐SiO₂ Mixed Oxide Materials

Abstract

The direct release of untreated wastewaters from various industries and households results in the release of toxic pollutants to the aquatic environment. Advanced oxidation processes (AOP) have gained wide attention owing to the prospect of complete mineralization of nonbiodegradable organic substances to environmentally innocuous products by chemical oxidation. In particular, heterogeneous photocatalysis has been demonstrated to have tremendous promise in water purification and treatment of several pollutant materials that include naturally occurring toxins, pesticides, and other deleterious contaminants. In this work, we have reviewed the different removal techniques that have been employed for water purification. In particular, the application of TiO2-SiO2binary mixed oxide materials for wastewater treatment is explained herein, and it is evident from the literature survey that these mixed oxide materials have enhanced abilities to remove a wide variety of pollutants.

Organic Contaminants in Refinery Wastewater: Characterization and Novel Approaches for Biotreatment

“…Diya'uddeen et al [2] and Rasalingam et al [14] presented detailed reviews on the diferent treatment technologies for RWW, with a focus on photocatalytic degradation as an advanced oxidation process (AOP). AOPs have gained extensive atention due to the possibility of destroying a wide variety of organic substances by chemical oxidation, resulting in complete mineralization [2,14].…”

“…AOPs have gained extensive atention due to the possibility of destroying a wide variety of organic substances by chemical oxidation, resulting in complete mineralization [2,14]. In particular, heterogeneous photocatalysis has been demonstrated to be a promising eicient and cost-efective technique for RWW treatment at an advanced stage.…”

“…During the adsorption, phenol is not degraded but rather transferred from the RWW to another phase, which results in the formation of serious by-products (secondary pollution). As such, regeneration is essential for reusing the activated carbon and for the collection and reuse of the contaminant substance [14,16]. Activated carbon is characterized by a wide variety of pores.…”

“…The adsorption process proceeds through a sequence of difusion steps from the bulk phase into the micropores, which are thought to be the major adsorption sites on activated carbon. Also, the amount adsorbed was reported to be positively inluenced by increased temperatures and decreased particle size of the adsorbent [14]. In adsorption, adsorbate-adsorbent interaction plays a key role.…”

“…In adsorption, adsorbate-adsorbent interaction plays a key role. The lack of such efective interaction results in only moderate adsorption capacity [14]. Adsorption isotherms are established by estimating uptake (or equilibrium adsorption capacity), q, calculated from the diference between the initial and the inal phenol concentrations as follows:…”