Recent Advances in 1,4-Dioxane Removal Technologies for Water and Wastewater Treatment

Abstract

1,4-Dioxane is a contaminant of emerging concern and a probable human carcinogen that has been widely detected in aqueous environments. However, the removal of 1,4-dioxane by conventional water and wastewater treatment plants had proven to be ineffective due to its unique physicochemical properties. The development of innovative technologies for both in-situ and ex-situ treatment of 1,4-dioxane to meet increasingly strict standards is in urgent need. This review summarizes the current available physicochemical and biological treatment technologies for the removal of 1,4-dioxane from both water and wastewater and the strategies that may potentially fulfill the stringent 1,4-dioxane standard were discussed. Advanced oxidation processes (AOPs), such as ultraviolet radiation coupled with H2O2 (8–10 mg L−1), had shown efficient 1,4-dioxane destruction and had already been applied for both water and wastewater treatment processes. On the other hand, more than 30 pure microbial strains and microbial communities that can metabolically or metabolically degrade 1,4-dioxane were reported. Biodegradation has been proven to be a feasible and cost-effective approach for 1,4-dioxane remediation. Suspended growth bioreactor, immobilized cell bioreactor, and biofiltration systems were the most commonly used biological approaches to remove 1,4-dioxane from contaminated water. Though 1,4-dioxane easily desorbs after the adsorption by materials such as granular activated carbon (GAC) and zeolite, temporary 1,4-dioxane removal by adsorption followed by 1,4-dioxane biodegradation in the bioaugmented adsorption media may be a feasible strategy treating 1,4-dioxane contaminated water. Overall, the treatment chain that combines physical-chemical processes and biodegradation has a great potential for synergistic removal of 1,4-dioxane at lower operating costs.

Adsorption Behavior and Kinetics of 1,4-Dioxane by Carbon Aerogel

“…Toxicological studies have indicated that exposure to 1,4-D can cause health harms such as nasal cavity carcinomas and liver and gall bladder carcinomas [ 5 ]. Therefore, it has been classified as a Group 2B probable human carcinogen by the International Agency for Research on Cancer (IARC) [ 6 ]. Data show that approximately 21% of the drinking water supplies in the United States are contaminated with 1,4-D [ 7 ].…”

“…Though 1,4-D is not federally regulated in the US, several states have established notification levels and guidelines. The acceptable concentrations of 1,4-D are low, typically in the range of (sub-) parts per billion (ppb), e.g., New York State set up a level of 1 µg L −1 , and several other states have established water criteria with the concentration ranging from 0.3 to 7.2 µg L −1 [ 6 ]. The prevalence, persistency, and toxicity of this emerging pollutant have prompted increasing attention, highlighting the necessity for cost-effective treatments to mitigate its exposure risk [ 8 ].…”

Surface Modification of TiO2/g-C3N4 Electrode with N, P Codoped CQDs for Photoelectrocatalytic Degradation of 1,4-Dioxane

“…1,4-dioxane (1,4-D) is an emerging organic pollutant with strong hydrophilicity and high stability in aqueous environments [1,2]. 1,4-D has been extensively detected in urban sewage systems, groundwater, and surface water worldwide [3][4][5].…”

“…1,4-D may cause serious damage in humans and environmental problems and has been classified a suspected carcinogen and an endocrinedisrupting chemical by reputable organizations such as the Agency for Toxic Substances and Disease Registry and the International Agency for Research on Cancer [9,10]. The concentration of 1,4-D in drinking water is recommended to be below 50 µg/L by the World Health Organization [1]. Due to a low Henry's law constant (4.80 × 10 −6 atm m 3 /mol at 25 • C) and high solubility, 1,4-D is difficult to remove using coagulation and adsorption [1,2].…”

“…The concentration of 1,4-D in drinking water is recommended to be below 50 µg/L by the World Health Organization [1]. Due to a low Henry's law constant (4.80 × 10 −6 atm m 3 /mol at 25 • C) and high solubility, 1,4-D is difficult to remove using coagulation and adsorption [1,2]. 1,4-D removal using conventional chlorine treatment may produce chlorinated byproducts that are more toxic than itself [10].…”