Enrichment Of The Various Chemical Elements In Seawater By The Electro-adsorption Technology

There are abundant chemical resources in seawater and the development and utilization of resources is imperative. The Electro-adsorption technology drives the ions to the electrode with opposite charge by applying electrostatic field. It has several important advantages, such as lower energy consumption, pollution, easier operation and so on. These advantages in the development and utilization of resources obtain attention of scientists. Porous carbon with well-developed pore structure and diverse BET property has been widely and successfully used as electrode materials. In this paper,the mesoporous carbon has been prepared and the porous carbon is prepared by activating later,and also investigated as an electrode material in electrochemical capacitors in seawater.In this paper,employing Polyether F127, Phloroglucin and Formaldehyde a novel micro-meso porous carbon (PC) was prepared by activation approach. The characterizations of the samples were carried out by TG-DTA, BET, XRD and SEM. The relationship of the heating rate,the carbonization time and BET and pore structure of mesoporous carbon has been researched. With potassium hydroxide as activator, a high surface area of porous carbon is prepared,examined influence of the experimental conditions for products performance. The results show that the specific surface area, pore volume and mesoporous surface area of the mesoporous carbon(MC) increase at beginning and then decrease with the increase of the heating rate and the decrease of the carbonization time. When the heating rate is 10℃/min, the largest mesoporous surface area and pore volume of mesoporous carbons can be prepared, which possess 324.47 m²·g^-1 specific surface area and 0.68 cm³·g^-1 pore volume and 8.44nm average pore size. When the ratio of KOH to mesoporous carbon is 4:1, the BET of porous carbons reaches 1345.52 m²·g^-1, the mesoporous specific surface area reaches 682.16 m²·g^-1 and the pore volume of 0.94 cm³·g^-1, the average pore size is 4.70nm and the range of pore sizes mainly are between 0 nm and 20 nm. The Electro- adsorption electrode was prepared by micro-meso porous carbon,the three-electrode electrochemical system is employed to test its electrochemical performance. When the ratio of KOH to mesoporous carbon is 4:1,the capacitance of porous carbon electrodes is up to 242.37 F·g^-1at a scan rate of 10 mv·S^-1 in seawater. In different scan rate, the electrode current as the voltage curve are quasi-rectangular shape, reflecting a good symmetry and capacitance characteristics. The Electro- adsorption unit by oneself is used to study the optimum conditions of seawater concentrated. The results show that the concentration tatio of Ca²⁺ in seawater up to the 111.75%, Mg²⁺ to 104.40%, K⁺ was 148.15%and Na⁺ was107.12%.