Removal of Typical Volatile Organic Compounds in Condensed Freshwater by Activated Persulfate during Interfacial Solar Distillation

Abstract

Recently, seawater desalination based on interfacial solar heating has attracted attention because of its environmental protection and high photothermal conversion efficiency. However, the high air–water interface temperature may cause freshwater quality safety risks because the volatile organic compounds (VOCs) in seawater are more likely to evaporate and condense into freshwater. In this work, typical VOCs (phenol) were prevented from entering into the condensed freshwater by using activated persulfate to take full advantage of interfacial solar distillation. The results showed that the addition of both peroxodisulfate (PDS) and peroxymonosulfate (PMS) could effectively reduce the concentration of phenol in condensed freshwater. The phenol’s distillation concentration rate (R D) was reduced from 74.4% to 14.3% with PMS and 20.5% with PDS. The Cl– was the main factor for activation of PMS, while carbon black, light, and heat were the main factors for activation of PDS. Meanwhile, PMS is better suited for removing VOCs due to its lower oxidant dosage and chlorinated disinfection byproducts compared with PDS. Finally, when real seawater samples were used as the source water for solar distillation, the water quality of typical indicators was lower than the limits set by Drinking Water Quality in China, US EPA, and WHO.

Integrated Multi-Layered Fabric with Tunable Water Supply to the Photothermal Conversion Layer for an Efficient Solar Water Evaporation

“…Traditional solar distillers have the disadvantage of low light–heat–steam conversion efficiency due to heating of the entire water body to promote water evaporation . In recent years, using solar energy to localize the heat at the water/air interface to drive the rapid evaporation of water has become very popular. − It has significantly enhanced the efficiency of steam generation and has become a rapidly growing research direction (Figure ). − So far, people have made substantial progress in fabricating high-efficiency solar steam generators through careful design, efficient light absorption, thermal management, and salt rejection strategies. ,− The preparation of a closed-cell 3D polymer foam via a controlled gas foaming technique, natural sunflower stalk pith with zwitterionic hydrogel coating, and diatom-inspired TiO 2 -PANi-decorated bilayer photothermal foam for solar-driven clean water generation are developed. ,, However, there are still huge challenges to make an integrated solar steam generator with multiple advantages of low cost and long-lasting durability …”

Surface Microlenses for Much More Efficient Photodegradation in Water Treatment

“…2−4 In some rural areas, especially remote regions, solar energy is one of the most popular resources to decontaminate water. 5,6 Compared to conventional wastewater treatment, photodegradation enhanced by catalysts 7−9 or sensitizers 10,11 can be highly efficient in removing pollutants that are hardly decomposed, such as antibiotics and personal care products. 12 However, currently low efficiency of light energy utilization and complexity associated with scaling up the size of solar energy collectors have hindered the applications of solar energy in fast conversion processes.…”

“…Earth receives abundant energy from the sunlight . Solar-driven photodegradation is a sustainable and effective strategy for wastewater treatment. − In some rural areas, especially remote regions, solar energy is one of the most popular resources to decontaminate water. , Compared to conventional wastewater treatment, photodegradation enhanced by catalysts − or sensitizers , can be highly efficient in removing pollutants that are hardly decomposed, such as antibiotics and personal care products . However, currently low efficiency of light energy utilization and complexity associated with scaling up the size of solar energy collectors have hindered the applications of solar energy in fast conversion processes. , Innovative designs are needed to maximize the water decontamination efficiency of the incident solar energy per unit surface area for water purification.…”

Layer-by-Layer-Assembled Loose Nanofiltration Membrane for Persulfate Activity Enhancement: Performance and Process Regulation

“…•− ) radical-based AOPs were among the processes explored for water purification. 6,7 Although deemed an applicable technology, the poor stability and pH dependence still become limitations in the employment of homogeneous AOPs. 8 Therefore, more research has been focused on heterogeneous AOPs.…”

“…Advanced oxidation processes (AOPs) capable of rapid production of reactive oxygen species (ROS) are considered as preeminent methods in view of their high micropollutant degradation efficiency . Recently, hydroxyl ( • OH) and sulfate (SO 4 •– ) radical-based AOPs were among the processes explored for water purification. , Although deemed an applicable technology, the poor stability and pH dependence still become limitations in the employment of homogeneous AOPs . Therefore, more research has been focused on heterogeneous AOPs. , Among them, peroxymonosulfate (PMS) activation is one of the research hotspots as its asymmetric molecule can be easily activated to generate • OH and SO 4 •– .…”