Combination of ozone-based advanced oxidation process and nanobubbles generation toward textile wastewater recovery

Abstract

The intricate nature of various textile manufacturing processes introduces colored dyes, surfactants, and toxic chemicals that have been harmful to ecosystems in recent years. Here, a combination ozone-based advanced oxidation process (AOP) is coupled with a nanobubbles generator for the generation of ozone nanobubbles (NB) utilized the same to treat the primary effluent acquired from textile wastewaters. Here we find several key parameters such as chemical oxygen demand ammonia content (NH3), and total suspended solids indicating a substantial recovery in which the respective percentages of 81.1%, 30.81%, and 41.98%, upon 300 min residence time are achieved. On the other hand, the pH is shifted from 7.93 to 7.46, indicating the generation of hydrogen peroxide (H2O2) due to the termination reaction and the self-reaction of reactive oxygen species (ROS). We propose that the reactive oxygen species can be identified from the negative zeta potential measurement (−22.43 ± 0.34 mV) collected in the final state of treatment. The combined method has successfully generated ozone nanobubbles with 99.94% of size distributed in 216.9 nm. This highlights that enhancement of ozone’s reactivity plays a crucial role in improving the water quality of textile wastewater towards being technologically efficient to date.

High Recovery of Ceramic Membrane Cleaning Remediation by Ozone Nanobubble Technology

“…It is worth mentioning that NB technology operates based on the occurrence of cavitation, which results from a significant decrease in pressure within the flow. Our previous research has demonstrated that our system achieved a cavitation number ( Cv ) of around 0.909 . According to Saharan et al, the cavitation phenomenon typically occurs when Cv ≤ 1. − …”

“…The oxidative agent was modified using a hydrodynamic cavitation process taking place in the NB generator. Initially, the pressurized ozone was injected into the water flow, following the methodology described in the previous studies. ,, The multiphase flow, consisting of ozone and water, passed through the honeycomb structure of the NB generator. As the multiphase flow traversed the honeycomb structure, the breakdown of the flow led to the subsequent formation of ozone NBs.…”

“…We used ∼30 g/L ozone with concentrated oxygen produced from a concentrator (Yuwell 8F-3AW) to achieve a purity level exceeding 90%. The NB generator employed in this study shares conceptual similarities with the orifice plate principle outlined in the previous research. , The plate dimension is 50.8 mm in diameter and within one unit comprising 15 sets of plates. The NB generator consists of 114 honeycomb-shaped holes with a diameter of 2.35 mm and a spacing of 1 mm.…”

“…Ozone is a promising oxidant in NB systems considering the high reduction potential. Additionally, in the ozone-NB system, ROS could potentially be generated not only by water pyrolysis but also by ozonation reaction through an indirect way. − NBs act as a physical barrier, effectively encapsulating the contaminating layers on its surface. − When contamination-encapsulated, the oxidant would oxidize it. Compared to larger bubbles, ozone-based NBs produced by NB generators exhibit a longer lifetime in the water column .…”

Characteristics and Stability of Ozone Nanobubbles in Freshwater Conditions

“…Of these 21 papers, eight measured NBs concentration in the solution. ,,,− However, these studies did not report the background particle levels, potentially overestimating the actual NBs concentration. Only six studies measured and reported the surface charge of ozone NBs. ,,,− Notably, none of the reviewed studies investigated the concentration change over time or the long-term stability of the ozone NBs. Only one study monitored the stability of ozone NBs in ultrapure water at pH 7–7.5, with the longest storage time being 14 days .…”