Hydrodynamic and kinetic study of a hybrid detoxification process with zero liquid discharge system in an industrial wastewater treatment

Abstract

This work focused on the degradation of toxic organic compounds such as methyl violet dye (MV) in water, using a combined photocatalysis/low pressure reverse osmosis (LPRO) system. The performance of the hybrid system was investigated in terms of the degradation efficiency of MV, COD and membrane separation of TiO2. The aim of the present study was to design a novel solar reactor and analyze its performance for removal of MV from water with titanium dioxide as the photocatalyst. Various operating parameters were studied to investigate the behavior of the designed reactor like initial dye concentration (C = 10-50 mg/L), loading of catalyst (CTiO2 = 200-800 mg/L), suspension flow rate (QL = 0.3-1.5 L/min), pH of suspension (5–10), and H2O2 concentration (CH2O2 = 200-1000 mg/L). The operating parameters were optimized to give higher efficiency to the reactor performance. Optimum parameters of the photocatalysis process were loading of catalyst (400 mg/L), suspension flow rate (0.5 L/min), H2O2 concentration (400 mg/L), and pH = 5. The designed reactor when operating at optimum conditions offered a degradation of MV up to 0.9527 within one hours of operation time, while a conversion of 0.9995 was obtained in three hours. The effluent from the photocatalytic reactor was fed to a LPRO separation system which produced permeate of turbidity value of 0.09 NTU which is closed to that of drinking water (i.e., 0.08 NTU). The product water was analyzed using UV-spectrophotometer and FTIR. The analysis results confirmed that the water from the Hybrid-System could be safely recycled and reuse. It was found that the kinetics of dye degradation was first order with respect to dye concentration and could be well described by Langmuir-Hinshelwood model. A power-law based empirical correlation was developed for the photocatalysis system, related the dye degradation (R) with studied operating conditions.

Photocatalytic, Antimicrobial and Biocompatibility Features of Cotton Knit Coated with Fe-N-Doped Titanium Dioxide Nanoparticles

“…Between many advantages, such as mineralization of toxic and bio-resistant organic compounds [1,2,3], and the inactivation of pathogenic microorganisms [4], one of the main limitations of using TiO 2 is the high quantity needed to obtain the desired effect.…”

Overview of Photocatalytic Membrane Reactors in Organic Synthesis, Energy Storage and Environmental Applications

“…In recent years, significant attention has been directed towards PMRs coupling photocatalysis in suspension and micro-(MF) or ultrafiltration (UF) processes [45,148], while only a few reports refer to PMRs with nanofiltration (NF) [32], reverse osmosis (RO) [149] or membrane distillation (MD) [150].…”

“…The schematic diagram of laboratory installation is presented in Figure 11. Abid et al [149] examined the degradation of methyl violet 6B (MV) dye in water using combined photocatalysis/low pressure reverse osmosis (LPRO) system. The investigations were focused on optimization of variable process parameters such as initial dye concentration (10-50 mg L −1 ), TiO 2 photocatalyst loading (200-800 mg L −1 ), suspension flow rate (Q L = 0.3-1.5 L min −1 ), pH (5-10), and addition of H 2 O 2 (200-1000 mg L −1 ).…”

“…The authors concluded that optimal parameters of the system were photocatalyst loading of 400 mg L −1 , Q L = 0.5 L min −1 , pH 5 and H 2 O 2 concentration of 400 mg L −1 . They also stated that the product of the hybrid process could be recycled and reused [149].…”

“…Schematic diagram of combined photocatalysis/low pressure reverse osmosis (LPRO) system to methyl violet dye removal[149].…”