Synthesis and Characterization of Carbon and Carbon-Nitrogen Doped Black TiO2 Nanomaterials and Their Application in Sonophotocatalytic Remediation of Treated Agro-Industrial Wastewater

Abstract

The conventional open ponding system employed for palm oil mill agro-effluent (POME) treatment fails to lower the levels of organic pollutants to the mandatory standard discharge limits. In this work, carbon doped black TiO2 (CB-TiO2) and carbon-nitrogen co-doped black TiO2 (CNB-TiO2) were synthesized via glycerol assisted sol-gel techniques and employed for the remediation of treated palm oil mill effluent (TPOME). Both the samples were anatase phase, with a crystallite size of 11.09–22.18 nm, lower bandgap of 2.06–2.63 eV, superior visible light absorption ability, and a high surface area of 239.99–347.26 m2/g. The performance of CNB-TiO2 was higher (51.48%) compared to only (45.72%) CB-TiO2. Thus, the CNB-TiO2 is employed in sonophotocatalytic reactions. Sonophotocatalytic process based on CNB-TiO2, assisted by hydrogen peroxide (H2O2), and operated at an ultrasonication (US) frequency of 30 kHz and 40 W power under visible light irradiation proved to be the most efficient for chemical oxygen demand (COD) removal. More than 90% of COD was removed within 60 min of sonophotocatalytic reaction, producing the effluent with the COD concentration well below the stipulated permissible limit of 50 mg/L. The electrical energy required per order of magnitude was estimated to be only 177.59 kWh/m3, indicating extreme viability of the proposed process for the remediation of TPOME.

Sonophotocatalysis with Photoactive Nanomaterials for Wastewater Treatment and Bacteria Disinfection

“…Doping with metal/nonmetal ions was employed to improve the catalytic activity of nanomaterials through numerous sonophotocatalytic degradation investigations. ,, Metallic dopants increase catalytic performance by forming impurity energy levels in the band gap. Equations and describe how incorporated metallic ions participate in the photocatalytic process of semiconductors.…”

“…The pseudo-first order kinetics of a sonophotocatalytic reaction system can be described according to eq . Also, the E EO (kWh/m 3 ·order) for an AOP can be calculated by eq log true( false[ italicC 0 false] false[ italicC false] true) = 0.4343 K app t E EO = 1000 × P e × t 60 × V × log true( false[ italicC 0 false] false[ italicC false] true) where K app (min –1 ) is the pseudo-first order rate constant, P e denotes the input power of electrical-energy-consuming source (kW), V is the volume of the reaction solution (L), t represents time (s), and C and C 0 are the concentrations of pollutant at time t and 0, respectively.…”

“…Rahman et al 60 explored the effect of H 2 O 2 addition on the chemical oxygen demand (COD) removal of palm oil mill effluent using C−N codoped black TiO 2 under Vis light and US irradiations. According to the obtained results, the sonophotocatalytic elimination of COD improved from 67.69% to 75.48% by the addition of 1.0 mM H 2 O 2 .…”

Preparation of Iron-Doped Titania Nanoparticles and Their UV-Blue Light-Shielding Capabilities in Polyurethane

“…Though some progress has been made in the field of TiO 2 -based UV light-shielding materials, several issues remain challenges. Due to the wide bandgap (3.0–3.2 eV), TiO 2 nanoparticles have limited UV absorption range (usually <380 nm) [ 15 ]. Moreover, high photocatalytic activity would accelerate the photodegradation of polymer materials.…”

Synthesis and Characterization of Manganese-Modified Black TiO2 Nanoparticles and Their Performance Evaluation for the Photodegradation of Phenolic Compounds from Wastewater

“…Photocatalysis has been used as a post-treatment approach for the photodegradation of phenolic compounds from TPOM by just a few research groups [ 16 , 17 ]. For example, Nawaz et al [ 18 ] found that 180 min of visible light irradiation removed 48.17 percent of phenolic chemicals from TPOME using black TiO 2 .…”