The Study On Anodic Modification Of Carbon Nanofibers In Electrochemically Regenerated Acid Etching Solution

With the rapid development of modern society,Printed Circuit Board(PCB),as an important part of computers and electronic products,has become increasingly prominent in economy and industry.Acidic etching solution is the most commonly used etching solution in the etching process of printed circuit boards.Its main components are copper chloride and hydrochloric acid.It contains a large amount of copper and has good economic and recycling value.Our country produces about 2 million tons of copper-containing etching waste every year,which contains about 200,000 tons of recyclable metallic copper,which is both a hazardous waste and a treasure house of resources.As the etching reaction progresses,the Cu(I)concentration in the acid etching solution gradually increases,and the etching effect on copper gradually deteriorates and eventually fails.If the acid etching waste liquid can be regenerated by an appropriate method,huge economic benefits will be produced due to the recycling of metallic copper and etching liquid recycling,and this is of great significance to the treatment of environmental pollution and the efficient use of resources.The existing acid etching solution recycling technology still has defects such as chlorine evolution at the anode electrode and high energy consumption cost.In this paper,the three-dimensional material of carbon nanofibers supported carbon nanotubes(VACNTs/CNFs)are prepared by the electrospinning method and the vapor deposition method(CVD method)and used for the electrolytic regeneration of the acid copper chloride etching solution.A new anode material with low energy consumption and inhibiting chlorine evolution.In this paper,the electrospinning method is used to prepare carbon nanofibers as the anode electrode of the electrochemical regeneration of PCB acid etching solution.The intermittent reaction tank is used to conduct electrolysis experiments on the etching waste solution,and the regeneration effect of the etching waste solution is investigated.When the current density is 30m A/cm~2 for electrolysis,the cell voltage is about 1.32 V and the anode potential is 0.67 V.The thesis further optimizes the physical and chemical properties of the electrochemical process by doping carbon nanotubes into the carbon nanofiber electrode.Compared with the initial carbon nanofibers,the carbon nanotube-doped carbon nanofibers(CNT-CNF)show more excellent surface affinity.Water and higher mass transfer efficiency,while having higher conductivity and electrochemical active area.In the electrochemical regeneration experiment of the PCB acid etching solution with CNT-CNF as the anode electrode,the electrode potential of 1.0 wt%CNT-CNF was 0.61 V,the average cell voltage of the reactor was 1.27 V,and the anode potential was always lower than 1 V during electrolysis.While electrocatalytic regeneration of the acid etching solution,the recovery of copper in the solution is realized and the occurrence of chlorine gas is effectively suppressed;however,the tank voltage cannot be significantly reduced,indicating that its energy-saving and consumption-reducing effect is not ideal.In order to further Improve current efficiency of carbon nanofiber electrode materials to lower their energy comsumption,the thesis used iron acetylacetonate,cobalt acetate,nickel acetate as the catalytic source,and polyvinylpyrrolidone(PVP)as the carbon source to grow carbon nano-particles by in-situ vapor deposition.The electrode material of carbon nanofibers supported carbon nanotubes(VACNTs/CNFs)was prepared,and the electrochemical activity of the three VACNTs/CNFs electrodes was investigated through CV curve and EIS curve,and its use in electrochemical regeneration of PCB acid etching solution was discussed.Studies have shown that,compared to carbon nanofibers without carbon nanotubes,the VACNTs/CNFs electrode materials using Co and Ni as catalysts exhibit super hydrophilicity,higher current efficiency,lower cell voltage and energy consumption,and the ability to inhibit chlorine evolution;the VACNTs/CNFs electrode material with Fe as the catalyst has poor hydrophilic wettability and worse electrocatalytic performance,which leads to an increase in cell voltage and energy consumption.Through comparison and screening,it is confirmed that Ni-VACNTs/CNFs have optimal acidic etching solution regeneration ability,and can effectively inhibit the chlorine evolution process with the lowest cell voltage and electric energy consumption.It is a new type of anode material with potential industrial application value.