A review of the textile wastewater treatment technologies with special focus on advanced oxidation processes (AOPs), membrane separation and integrated AOP-membrane processes

Ultrasound-Assisted Catalytic Ozonation-Based Treatment of Rare-Earth Processing Effluent Containing Ammonium Thiocyanate (NH4SCN)

“…It is thus obvious that adding more H 2 O 2 than necessary reduces the COD reduction attributed to the scavenging action by excess H 2 O 2 or the recombination reaction of the extra OH radicals, 38 which reduces the availability for the desired oxidation of contaminants. Optimum dosing needs to be determined specifically for the type of effluent to be treated, 11 emphasizing the importance of conducting detailed research into understanding the effect of operating conditions in the current work. The results for the variation in the H 2 O 2 loading studied over 800 to 1400 ppm on the changes in COD of REI effluent for hybrid approach of US + O 3 + H 2 O 2 at optimized pH of 12 are shown in Figure 6, and the values of rate constants obtained at different loadings are shown in Table S3.…”

“…In recent times, Advanced Oxidation Processes (AOPs) are regarded as a promising technique for effective degradation of molecules which are resistive to chemical and biological oxidation. 10 AOPs include cavitation (acoustic and hydrodynamic), photocatalytic oxidation, ozonation, H 2 O 2 (hydrogen peroxide), and Fenton's reagent, all of which produce highly oxidizing free hydroxyl (OH) radicals, 11 which attack pollutants to break the bonds and eventually oxidize them into CO 2 , H 2 O, and inorganic salts through oxidation, dehydrogenation or hydroxylation. 12 To the best of our analysis, no previous work was reported on using ultrasound (US) for the degradation of ammonium thiocyanate (NH 4 SCN), even though ultrasound-based approaches can be promising for the degradation of biorefractory molecules.…”

Lamellar MXene Nanofiltration Membranes for Electrostatic Modulation of Molecular Permeation: Implications for Fine Separation

“…Membrane-based separation, combined with the advantages of low energy consumption and high efficiency, has gradually become the mainstream technique for diverse fine separation processes, such as water treatment, organics purification, olefin/paraffin separation, gas separation, and so on . Among them, nanofiltration has shown special applications in this area owing to its effective separation abilities on smaller species including inorganic salts and small organic molecules. − However, subjected to the limitations of the inherent size- and Donnan-exclusion separation mechanisms, the separation properties of most as-formed nanofiltration membranes are usually determined and difficult to be further modified. , By combining special substances such as pH-sensitive modifiers or advanced oxidation species, − the separation performance of some nanofiltration membranes can be adjusted. Nevertheless, the integration of these auxiliary agents may introduce some new problems to the separation properties (for instance, the stability under specific operation conditions) and put forward higher requirements for the preparation of these membranes with a suitable filtration function.…”

Water Recovery from Highly Saline Dye Wastewater by Membrane Distillation Using a Superhydrophobic SiO2/PVDF Membrane

“…However, the disadvantages in technologies (e.g., low removal for chemical oxygen demand, unstable system, and long-term maintenance cost) gradually limited their applications in dye wastewater treatment. More alarmingly, such shortcomings are incapable of being addressed completely only by simple integration of these conventional processes. − Therefore, advanced technologies urgently need to be developed to tackle such a challenging dye waste stream.…”