Effect of Electrode Surface Structure and Wettability on the Physical Characteristics of Hydrogen Bubbles During Electroflotation
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摘要:
研究了电浮选中多孔镍阴极的微观结构及润湿性变化对氢气泡特征的影响。通过酸法刻蚀及氟硅烷表面改性处理，考察处理前后多孔镍阴极表面微观结构及润湿性变化对氢气泡尺寸、浓度和上升速度的影响。结果表明，酸法刻蚀可提高多孔镍阴极材料表面的粗糙度，增加电极的裂纹、裂隙及溶出粒子间的孔隙；经酸法刻蚀处理后，电极的亲水性显著提高，并且随着刻蚀时间的增加，多孔镍阴极表面亲水性增强；氟硅烷改性可使多孔镍阴极表面疏水化，且其表面经刻蚀粗糙化处理后，氟硅烷的改性效果更显著；多孔镍阴极表面亲水性越强，电解产生的氢气泡尺寸越小，气泡浓度或气泡生成量越高，反之亦然；在电解氢气泡的尺度范围内，气泡上升速度与尺寸呈线性相关，气泡尺寸越大，上升速度越快。
Abstract:This paper studied the influence of porous nickel cathode microstructure and wettability on the characteristics of electrolytic hydrogen bubbles in the electroflotation. The porous nickel electrode was treated by acid etching and surface modification of fluorosilane. The influence of the microstructure and wettability of the treated porous nickel cathode on the size, concentration and rising speed of hydrogen bubble was investigated. The results show that acid etching can improve the surface roughness of porous nickel cathode materials and increase the cracks and pores produced by etching Ni particles. The hydrophilicity of the porous nickel cathode has been increased significantly after acid etching, and the surface hydrophilicity also has been increased with the continuation etching. The fluorosilane modification can increase the hydrophobicity of the electrode surface, and the fluorosilane modification become more significant after the etching pretreatment of the electrode. the more hydrophilic the electrode surface, the smaller in size, the higher in concentration and accumulation the produced hydrogen bubble, and vice versa. In the scale range of the hydrogen bubble produced on the porous nickel cathode, the rising speed of bubble is linearly related to the size. The larger the bubble size becomes, the quicker the rising speed increases.
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Key words:
- electroflotation /
- electrode surface structure /
- wettability /
- hydrogen bubble /
- physical characteristic
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表 1 不同刻蚀时间及氟硅烷改性前后镍电极表面润湿性
Table 1. Surface wettability of nickel electrodes with etching treatment and fluorosilane modification
Treatment type Acid etching Modified after etching Etching time 0 89° 135° 10 t=8.0 147° 15 t=5.4 148° 20 t=1.0 148° 25 t=0.5 154° 30 t=0.2 155° Where, “°” is the equilibrium contact angle measured by static contact angle mode, and “t=” is the spreading time measured by dynamic contact angle measurement mode。 
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