Nonflammable superhydrophobic passive cooling Cellulose-CaCO3 film.

Energy consumption from air cooling systems in summer, water scarcity in hot regions, and the functional reusability of waste paper are emerging environmental problems. Finding solutions to these problems simultaneously remains a significant challenge. Herein, a superhydrophobic passive cooling Cellulose-CaCO3 film with hierarchical nano-sheets was fabricated to realize daytime radiative cooling with a temperature drop of 15-20 °C in summer and water harvesting with harvesting efficiency of 387 mg cm-2h-1 bd utilization of recycled waste paper. The superhydrophobic Cellulose-CaCO3 film demonstrates its self-cleaning properties against inorganic and organic pollutants. Furthermore, the superhydrophobicity of the film was maintained after base/acid corrosions, dynamic water flushing, and thermal treatment at 100 °C for 7 h, exhibiting good durability of the superhydrophobicity. Moreover, the superhydrophobic Cellulose-CaCO3 film is nonflammable after exposure to fire combustion for 1 min. In addition to waste paper, waste maize straws, and pasteboards were also collected to produce superhydrophobic passive cooling films. Results indicate that the above three cellulose-based raw materials can be well used to prepare durable superhydrophobic passive cooling materials. Environmental toxicology assessments confirm the safety of the material. This study not only provides a protocol for preparing superhydrophobic materials; but also demonstrates their potential for passive cooling and water harvesting.

Ecological and human health hazards of soil heavy metals after wildfire: A case study of Liangshan Yi autonomous prefecture, China.

Soil samples were collected in at different depths from the conflagration area in Liangshan Yi Autonomous Region, China, to investigate the distribution characteristics and ecological and human health risks of heavy metals after a wildfire. The samples collected comprise wildfire ash (WA) above the soil surface, ash soil (AS) 0-5 cm, and plain soil (PS) 5-15 cm below the soil surface. Additionally, reference soil (RS) was collected from a nearby unburned area at the same latitude as the conflagration area. The results showed that the concentrations of zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd) in the WA and AS were significantly higher than in reference soil (RS) (p < 0.05). Concentrations of Pb in the PS were 2.52 times higher than that in RS (17.9 mg kg-1) (p < 0.05). The AS and WA had the highest Index of potential ecological risks (RI > 600). In addition, The Cd in AS and WA contributed the most to the highest Improved nemerow index (INI) and RI with a contribution of more than 80%. The concentration of heavy metals was used to establish non-carcinogenic effects and cancer risks in humans via three exposure pathways: accident ingestion of soil, dermal contact with soil, and inhalation of soil particles. Hazard index (HI) values of each sample were all less than 1, indicating the non-carcinogenic risk was within the acceptable range and would not adversely affect the local population's health. The Cancer risk (CR) values of Cr, As, Cd, and Ni were all below 1 × 10-6, indicating that heavy metal pollution from this wildfire did not pose a cancer risk to residents.

Dual Superlyophobic Materials for Under-Liquid Microfluid Manipulation, Immiscible Solvent Separation, and CO2 Blockage.

Oily water purification, immiscible solvent separation, sensitive microreaction, and CO2 blockage are of great interest because of their importance for the environment and demands of controllable microreactions. However, one specific material that can meet all the requirements has yet to be reported. Herein, we developed a simple environment-benign method to prepare specific dual superlyophobic materials to solve the problems mentioned earlier. The dual superlyophobic materials can maintain their dual superoleophobicity in various oil/water systems, and no additional surface modifications were required when the oil/water system was changed. Moreover, the materials can be used to separate oil/water mixtures with separation efficiencies greater than 99.50% even after 40 separation cycles and separate immiscible organic solvents with efficiencies over than 99.25% after 20 cycles. Separations of meal waste oily water at 60 °C and crude oil/water were also successfully performed. The materials can be further applied to manipulate and block CO2 bubbles under liquid. The materials can also act as a platform for microdrop manipulation/microreaction under liquid.