Study On The Preparation And Performance Of Porous Cellulose-based Light-to-heat Conversion Gel Material

The shortage of water resources is an important problem to be solved urgently at present.Solar water evaporation technology has become one of the current research hotspots because it belongs to the use of renewable clean energy and has no secondary pollution.In order to achieve efficient and green solar water evaporation in this paper,a natural cellulose with a wide range of sources,naturally degradable and strong hydrophilicity was selected as the matrix material,and a porous cellulose gel material was prepared by the sol-gel method.A conductive carbon-based material is hybridized to prepare an interface-type porous cellulose-based light-to-heat conversion gel material with adjustable structure.The specific research content is as follows:（1）The porous cellulose gel material（PCG）was prepared by a sol-gel method using a zinc chloride aqueous solution and a urethane-alkali solution as dissolution systems,and the effect of cellulose content on the structure of PCG was investigated.The study found that the PCG structure can be achieved by adjusting the cellulose content.In the zinc chloride aqueous system,when the cellulose content is 5 wt.%,the prepared PCG has a high porosity and three-dimensional network structure with multi-stage pore size;in the urethane-alkali system,when the cellulose content is 7 wt.%,the porosity of the prepared PCG is high,the pore size distribution is narrow,and a honeycomb-like pore structure is formed.（2）Activated carbon/porous cellulose light-to-heat conversion gel material（AC-PCG）and multi-walled carbon nanotubes/porous cellulose light-to-heat conversion gel material are prepared by using a zinc chloride aqueous solution as a dissolution system by hybridizing conductive carbon-based materials of different sizes,that is,micron-sized activated carbon（AC）and nano-sized multi-walled carbon nanotubes（CNTs）,and investigated the effects of the content of conductive carbon-based materials on their structure and water evaporation properties.Through research,it is found that under the light intensity of 1 k W·m^-2,when the AC content is 1.5 wt.%and the CNTs content is0.1 wt.%,the maximum water evaporation rates of the prepared AC-PCG and CNTs-PCG are respectively 1.239 kg·m^-2·h^-1 and 1.106 kg·m^-2·h^-1,the corresponding water evaporation efficiencies are 80.1%and 70.0%,respectively,in which the water evaporation rate is the pure water control group(0.563 kg·m^-2·h^-1 and 0.516 kg·m^-2·h^-1)2.6 and 2.3 times,the highest temperature can reach 42.1℃and 40.6℃,respectively.（3）AC-PCG and CNTs-PCG were prepared by adding AC and CNTs,respectively,using a urethane-alkali solution as a dissolution system.The effects of the addition of AC and CNTs on the structure and water evaporation properties of porous cellulose-based light-to-heat conversion gel materials were also investigated.The research shows that under the light intensity of 1 k W·m^-2,when AC content is 3.5 wt.%and CNTs content is 0.2 wt.%,the prepared AC-PCG and CNTs-PCG have the highest water evaporation rate,1.021 kg·m^-2·h^-1 and 1.274 kg·m^-2·h^-1,respectively.And the corresponding water evaporation efficiencies are 66.5%and 82.3%,respectively.They are pure water control groups(0.263 kg·m^-2·h^-1 and 0.307 kg·m^-2·h^-1)3.6 times and 4.2times,the highest temperature can reach 43.2℃and 44.4℃,respectively.