Ultrablack materials have attracted wide attention due to their high light absorbance and efficient photothermal conversion used in the field of solar steam generation to alleviate the drinking water crisis. Herein, ultrablack and low‐cost poly(vinyl alcohol)‐graphite composite xerogels (PGCXs) that have vertically arranged pores and high thermal conductivities are fabricated. The PGCX‐50% shows high light absorbance (95.44%), good wettability, and a water evaporation rate of 1.24 kg m−2 h−1 under 1 sun illumination when coupled in a two dimensional (2D) evaporator. To further improve the solar steam generation performance, the PGCX‐50% is switched to a three dimensional (3D) evaporator by rotating it. Under 1 sun illumination, the 3D evaporator has a highest water evaporation rate of 3.80 kg m−2 h−1, which is 3.07 times that of the 2D evaporator, due to its larger evaporation area and higher surface area at subambient temperature. Finally, a heatsink‐like 3D evaporator is designed and a water evaporation rate of up to 9.54 kg m−2 h−1 is achieved when coupled with wind energy. The high water evaporation rates of the PGCX even in concentrated brines ensure its great potential for drinking water production and seawater desalination.
The goal of this study is to enhance secession ability of adsorbed water in the fine particles of sludge from waste treatment plant using ultrasonic wave energy. Results of the treatment involving reduction in the final sludge cake affect the usage of energy required for sludge combustion. Excess activated sludge before dewatering process was sampled in the local area and the test conditions included application time and power of the ultrasonic energy and types of flocculants to investigate the dewatering behaviors. Capillary suction time(CST) and viscosity of the tested sample were the main indicator for the dewaterbility of the treated sludge. The results of the study show that the ultrasonic treatment decreases the dewaterbility of sludge sample significantly. The degree of the effectiveness, however, varies with the test conditions. Energy and cost reduction caused by the ultrasonic treatment are also discussed in detail.
Abstract. The use of vibrational energy to enhance the filterability of drainage was investigated with a series of laboratory tests. Test conditions included frequencies, power and duration of sonic energy and curing time. Results indicated that the use of sonic waves in the filtering process significantly enhanced the efficiency of filters. A visible decrease in the flow fouling was also observed. The degree of enhancement varied with sonication energy, and treatment time.
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