Nuclear chemistry

Quantum mechanics

Reaction rate constant

Photochemistry

Ultraviolet visible spectroscopy

Telecommunications

Alkyl

Computer science

Brilliant green

Physics

Cationic polymerization

Organic chemistry

Degradation (telecommunications)

Aqueous solution

Kinetics

Chemistry

Photodissociation

Journal of Hazardous Materials

The removal of brilliant green (BG), a toxic organic and cationic dye, has been examined by UV/S2O82- (PS), UV/HSO5- (PMS) and UV/H2O2 processes. BG showed insignificant direct photolysis at 254 nm (i.e., 8.6% after 30 min). However, enhanced BG degradation was observed in UV/PS, UV/PMS and UV/H2O2 systems as revealed from 63.1, 47.0 and 34.8% BG degradation, respectively, at 30 min of reaction time, using 0.05 mM BG and 1.0 mM oxidant initial concentration. The bimolecular rate constants of OH and SO4- with BG were determined to be 2.35 × 109 and 2.21 × 109 M-1 s-1, respectively. Electrical energy per order (EE/O) values for UV/PS, UV/PMS and UV/H2O2 processes were calculated to be 5.4, 6.8, and 7.8 KWh/m3/order, respectively. The addition of humic acid (HA) and inorganic anions inhibited the degradation of BG by UV/PS in the order of NO2- > HA > HCO3- > Cl- > NO3- ≈ SO42-. The results of frontier electron densities (FEDs) showed that C-atom holding the three rings (C7), and C-atoms at para positions to N-alkyl groups of the two rings (C4 and C14) are the predominant sites for radical addition. Furthermore, nine degradation products (DPs) of BG were detected experimentally using LC/MS/MS.

Oxidative removal of brilliant green by UV/S2O82‒, UV/HSO5‒ and UV/H2O2 processes in aqueous media: A comparative study