ABSTRACT
Photocatalysis appears to be an appealing approach for environmental remediation including pollutants degradation in water, air, and/or soil, due to the utilization of renewable and sustainable source of energy, i.e., solar energy. However, their broad applications remain lagging due to the challenges in pollutant degradation efficiency, large-scale catalyst production, and stability. In recent decades, massive efforts have been devoted to advance the photocatalysis technology for improved environmental remediation. In this review, the latest progress in this aspect is overviewed, particularly, the strategies for improved light sensitivity, charge separation, and hybrid approaches. We also emphasize the low efficiency and poor stability issues with the current photocatalytic systems. Finally, we provide future suggestions to further enhance the photocatalyst performance and lower its large-scale production cost. This review aims to provide valuable insights into the fundamental science and technical engineering of photocatalysis in environmental remediation.
Subject(s)
Environmental Pollutants , Environmental Restoration and Remediation , Solar Energy , Technology , Soil , CatalysisABSTRACT
Solar-driven evaporation is a promising technology for desalinating seawater and wastewater without mechanical or electrical energy. The approaches to obtaining fresh water with higher evaporation efficiency are essential to address the water-scarcity issue in remote sensing areas. Herein, we report a highly efficient solar evaporator derived from the nanocomposite of anatase TiO2/activated carbon (TiO2/AC), which was coated on washable cotton fabric using the dip-dry technique for solar water evaporation. The ultra-black fabric offers enhanced solar absorption (93.03%), hydrophilic water transport, and an efficient evaporation rate of 1.65 kg/m2h under 1 kW m-2 or one sun solar intensity. More importantly, the sideways water channels and centralized thermal insulation of the designed TiO2/AC solar evaporator accumulated photothermal heat at the liquid and air interface along with an enhanced surface temperature of 40.98 °C under one sun. The fabricated solar evaporator desalinated seawater (3.5 wt%) without affecting the evaporation rates, and the collected condensed water met the standard of drinking water set by the World Health Organization (WHO). This approach eventually enabled the engineering design groups to develop the technology pathways as well as optimum conditions for low-cost, scalable, efficient, and sustainable solar-driven steam generators to cope with global water scarcity.
ABSTRACT
Solar-driven water evaporation is of great importance for freshwater production via solar distillation and has attracted growing attention recently by the development of heat localization strategies. Yet, when polluted water is used as the source water, solar-driven water evaporation might further deteriorate the pollution. In this study, we report the facile preparation of multifunctional Ag3PO4-reduced graphene oxide (Ag3PO4-rGO) nanocomposite-coated textiles for clean water production by solar-driven water evaporation, photocatalysis, and disinfection. The multifunctional textiles are obtained through coating Ag3PO4-rGO nanocomposites onto cotton textile substrates. The resulting textile can float on the water surface, absorb solar light, and convert it into heat, enhancing the water surface temperature and promoting water evaporation. We show that with Ag3PO4-rGO nanocomposite-coated textiles on the water surface, a high water evaporation rate of 1.31 kg/(m2 h) can be reached under solar light irradiation. Furthermore, the textiles can simultaneously decompose organic dyes and disinfect pathogenic microbes in water, purifying the raw water during solar-driven water evaporation. Such an all-in-one multifunctional textile provides a facile yet sustainable strategy for freshwater production.
ABSTRACT
In this report, we present a facile approach to produce biodegradable polymeric microparticles with uniform sizes and controllable morphologies by blending hydrophobic poly(d, l-lactic-co-glycolide) (PLGA) and amphiphilic poly(d, l-lactic acid)-b-poly(ethylene glycol) (PLA-b-PEG) in a microfluidic chip. Microparticles with tentacular, hollow hemispherical, and Janus structures were obtained after complete evaporation of the organic solvent by manipulating the interfacial behavior of emulsion droplets and the phase separation behavior inside the droplets. The number and length of the tentacles on the surface of tentacular microparticles could be tailored by varying the initial concentration and blending ratios of the polymers. The organic solvent played an important role in controlling the morphologies of microparticles. For example, blending PLA16k-b-PEG5k with PLGA100k in dichloromethane resulted in tentacular microparticles, whereas hollow hemispherical microparticles were obtained in trichloromethane. Moreover, these microparticles with controllable shapes and surface textures have significant influence on the immune response of dendritic cells (DCs), showing a morphology-dependent enhancement of DC maturation.
