The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a p...The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a polished titanium cathode.Effects of initial nickel citrate concentration,current density,initial p H,electrode spacing,electrolyte type,and initial electrolyte dosage on electrochemical performance were examined.The efficiencies of Ni(Ⅱ)-citrate removal and nickel metal recovery were determined to be 100%and over 72%,respectively,under the optimized conditions(10 m A/cm^(2),pH 4.09,80 mmol/L Na_(2)SO_(4),initial Ni(Ⅱ)-citrate concentration of 75 mg/L,electrode spacing of 1 cm,and 180 min of electrolysis).Energy consumption increased with increased current density,and the energy consumption was 0.032 kWh/L at a current density of 10 m A/cm^(2)(pH 6.58).The deposits at the cathode were characterized by scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%.The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.展开更多
The current efficiency for NF3 formation was independent on the current density in the range of 200 to 1,000 mA·cm^2. The average values of NF3 current efficiencies on the BDD （boron-doped diamond） anode with t...The current efficiency for NF3 formation was independent on the current density in the range of 200 to 1,000 mA·cm^2. The average values of NF3 current efficiencies on the BDD （boron-doped diamond） anode with the boron-concentration of 2,500 ppm were 32.3% at 80℃, 63.3% at 100℃ and 59.7% at 120℃. The best current efficiencies for NF3 formation on the BDD anode with boron-concentrations of 2,500, 5,000 and 7,500 ppm were obtained at 100℃ and those were 63.3%, 73.3% and 56.2%, respectively. Although anode effect occurred on the BDD electrodes covered with a part of the surface of the spiculate structure, which had the boron-concentrations higher than 7,500 ppm, it did not take place on the BDD electrodes covered with the surface of diamond structure, even if the BDD electrode had the boron-concentration of 8,000 ppm.展开更多
This paper presents a new cleaning process for particle and organic contaminants on polished silicon wafer surfaces.It combines a non-ionic surfactant with boron-doped diamond（BDD） film anode electrochemical oxidati...This paper presents a new cleaning process for particle and organic contaminants on polished silicon wafer surfaces.It combines a non-ionic surfactant with boron-doped diamond（BDD） film anode electrochemical oxidation. The non-ionic surfactant is used to remove particles on the polished wafer＇s surface,because it can form a protective film on the surface,which makes particles easy to remove.The effects of particle removal comparative experiments were observed by metallographic microscopy,which showed that the 1%v/v non-ionic surfactant achieved the best result. However,the surfactant film itself belongs to organic contamination,and it eventually needs to be removed.BDD film anode electrochemical oxidation（BDD-EO） is used to remove organic contaminants,because it can efficiently degrade organic matter.Three organic contaminant removal comparative experiments were carried out：the first one used the non-ionic surfactant in the first step and then used BDD-EO,the second one used BDD-EO only,and the last one used RCA cleaning technique.The XPS measurement result shows that the wafer＇s surface cleaned by BDD-EO has much less organic residue than that cleaned by RCA cleaning technique,and the non-ionic surfactant can be efficiently removed by BDD-EO.展开更多
基金supported by Major Science and Technology Program for Water Pollution Control and Treatment in China(No.2017ZX07202-001-007)the National Science Fund for Distinguished Young Scholars(No.51625801)+4 种基金the Guangdong Innovation Team Project for Colleges and Universities(No.2016KCXTD023)Guangdong Provincial Science and Technology Project(No.2017A020216014)the National Science Fund,China(No.21777106)Pearl River S&T Noval Program of Guangzhou,China(No.201710010065)the key projects of Dongguan social science and technology development plan(No.2019507140204)。
文摘The simultaneous electro-oxidation of Ni(Ⅱ)-citrate and electrodeposition recovery of nickel metal were attempted in a combined electro-oxidation-electrodeposition reactor with a boron-doped diamond(BDD)anode and a polished titanium cathode.Effects of initial nickel citrate concentration,current density,initial p H,electrode spacing,electrolyte type,and initial electrolyte dosage on electrochemical performance were examined.The efficiencies of Ni(Ⅱ)-citrate removal and nickel metal recovery were determined to be 100%and over 72%,respectively,under the optimized conditions(10 m A/cm^(2),pH 4.09,80 mmol/L Na_(2)SO_(4),initial Ni(Ⅱ)-citrate concentration of 75 mg/L,electrode spacing of 1 cm,and 180 min of electrolysis).Energy consumption increased with increased current density,and the energy consumption was 0.032 kWh/L at a current density of 10 m A/cm^(2)(pH 6.58).The deposits at the cathode were characterized by scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These characterization results indicated that the purity of metallic nickel in cathodic deposition was over 95%.The electrochemical system exhibited a prospective approach to oxidize metal complexes and recover metallic nickel.
文摘The current efficiency for NF3 formation was independent on the current density in the range of 200 to 1,000 mA·cm^2. The average values of NF3 current efficiencies on the BDD （boron-doped diamond） anode with the boron-concentration of 2,500 ppm were 32.3% at 80℃, 63.3% at 100℃ and 59.7% at 120℃. The best current efficiencies for NF3 formation on the BDD anode with boron-concentrations of 2,500, 5,000 and 7,500 ppm were obtained at 100℃ and those were 63.3%, 73.3% and 56.2%, respectively. Although anode effect occurred on the BDD electrodes covered with a part of the surface of the spiculate structure, which had the boron-concentrations higher than 7,500 ppm, it did not take place on the BDD electrodes covered with the surface of diamond structure, even if the BDD electrode had the boron-concentration of 8,000 ppm.
文摘This paper presents a new cleaning process for particle and organic contaminants on polished silicon wafer surfaces.It combines a non-ionic surfactant with boron-doped diamond（BDD） film anode electrochemical oxidation. The non-ionic surfactant is used to remove particles on the polished wafer＇s surface,because it can form a protective film on the surface,which makes particles easy to remove.The effects of particle removal comparative experiments were observed by metallographic microscopy,which showed that the 1%v/v non-ionic surfactant achieved the best result. However,the surfactant film itself belongs to organic contamination,and it eventually needs to be removed.BDD film anode electrochemical oxidation（BDD-EO） is used to remove organic contaminants,because it can efficiently degrade organic matter.Three organic contaminant removal comparative experiments were carried out：the first one used the non-ionic surfactant in the first step and then used BDD-EO,the second one used BDD-EO only,and the last one used RCA cleaning technique.The XPS measurement result shows that the wafer＇s surface cleaned by BDD-EO has much less organic residue than that cleaned by RCA cleaning technique,and the non-ionic surfactant can be efficiently removed by BDD-EO.
