葡萄糖还原法制备氧化亚铜的研究

【作者】 曹艳；

【导师】 周康根；

【作者基本信息】 中南大学 ， 环境工程， 2009， 硕士

【摘要】 氧化亚铜是一种重要的无机化工原料,在诸多领域有着广泛的应用。目前氧化亚铜的制备方法主要包括固相法、电解法和液相法等,其中液相法因设备投资省、有利于形貌与粒度控制而得到了广泛的研究。然而很多合成工艺采用如水合肼、亚硫酸钠等一些毒性较大的物质为还原剂,环境治理成本较高。本研究的目的是开发以葡萄糖为还原剂的环境友好的氧化亚铜制备方法。本文在碱性环境和不加任何添加剂条件下通过葡萄糖还原1.0mol/L的Cu（Ⅱ）,采用升温法和定温法制备超细Cu₂O粉体。升温法是先将反应物在室温下混合,然后以一定的速度升温至终点温度进行反应;而定温法是反应物在恒定的温度下进行反应。具体研究内容归纳如下:在升温法制备超细Cu₂O中,研究了反应终点温度、葡萄糖浓度和搅拌速度等因素对Cu₂O粒子的影响。实验结果表明,反应终点在温度为50～80℃之间,Cu₂O形貌不受其影响,均以聚集模式长大为球形颗粒;随反应终点温度升高,Cu₂O平均粒径呈现先减小后增大的趋势,但变化范围不大（0.68～0.95μm）。当葡萄糖浓度为1.0～2.0mol/L时,得到了以聚集模式长大的球形Cu₂O颗粒,平均粒径相应为0.99～0.74μm;随葡萄糖浓度的升高,Cu₂O平均粒径减小,粒度分布更均匀。当葡萄糖处于低浓度（0.5mol/L）,得到了以二维成核生长模式长大的方形Cu₂O颗粒;在200～600rmp范围内,改变搅拌速度对球形Cu₂O粒径的影响无规律。以本方法制备出Cu₂O平均粒径在0.7～1μm之间,存在问题是无法得到粒径更大的Cu₂O。在定温法制备超细Cu₂O中,研究了加料方式、反应温度、反应时间和葡萄糖浓度等因素对Cu₂O形貌与粒度的影响。实验结果表明,加料方式对Cu₂O的分散性有重要的影响,以CuSO₄与NaOH混合反应后加入葡萄糖还原得到的Cu₂O分散性最好。反应温度同时影响Cu₂O形貌与粒径,当反应温度在40～60℃之间时,生成以聚集模式长大的、平均粒径为1.42～0.78μm的球形Cu₂O颗粒;当反应温度高于60℃,生成以聚集模式与二维成核模式共同作用长大的球形和方形混合晶形Cu₂O。在20～120min之间的反应时间对Cu₂O的形貌和粒径没有明显影响。葡萄糖浓度对Cu₂O形貌与粒径有显著影响,当葡萄糖浓度由0.25mol/L逐渐升高到2.0mol/L,Cu₂O晶体生长模式由（100）面位错生长模式占主导地位过渡为二维成核生长模式,直至最后转变为聚积生长模式,晶体形貌从八面体、类球形、立方体与球形混合颗粒向球形多晶过渡;葡萄糖浓度为0.4～2.0mol/L时,生成平均粒径为2.71～1.08μm的球形Cu₂O颗粒。两种方法对比,定温法控制条件简单,得到的Cu₂O粒径分布均匀,比升温法更适合于Cu₂O粉体的制备。更多还原

【Abstract】 Cuprous oxide is an important inorganic industrial chemical and widely applied in many fields.Among the main preparation methods of Cu₂O particles,the liquid phase methods are most widely investigated because their advantages those equipments are simple and control of particle morphology and size is easy.However,the use of poisonous chemicals as reductants such as N₂H₄ and Na₂SO₃ causes a high environmental protection costs in many processes.The purpose of this work is to development a green production process of Cu₂O particle using glucose as a reduction agent.In this work,Cu₂O particles were prepared via reducing 1.0mol/L Cu（Ⅱ） with glucose under alkaline condition without any additive,using rising temperature method and constant temperature method.In the rising temperature method,the reactants are mixed at room temperature at first, then rise to reaction end-point temperature at a constant temperature rising rate.In the constant temperature method,the reactants are mixed at given temperature and then react.The results are summarized as follows:Concerning the preparation of Cu₂O particles with rising temperature method,the influence of the reaction end-point temperature, the glucose concentration and stiring rate on the morphology and size of Cu₂O particles were studied.The results show that the morphology of Cu₂O particles is not remarkably affected by the end-point temperature change from 50℃to 80℃and spherical particles are obtained as a result of aggregation growth mode.The average size of Cu₂O particles first increases and then decreases with increasing temperature,but change in the average size is not wide（0.68μm to 0.95μm）.When glucose concentration changed from 1.0 mol/L to 2.0mol/L,the spherical Cu₂O particles with average size 0.99μm to 0.74μm are obtained as a result of aggregation growth mode.The average size of Cu₂O particles becomes smaller and more uniform with increasing the glucose concentration. When the glucose concentration was 0.5mol/L,the cubic Cu₂O particles were obtained as a result of two-dimensional nucleation growth mode. The stiring rate has ruleless effect on the size of Cu₂O particles at the rage of 200rpm to 600rpm.The average sizes of Cu₂O particles among 0.6～1.0μm were obtained with this method,but the larger sizes of Cu₂O particles are hardly obtained.Concerning the preparation of Cu₂O particles with constant temperature method,the influence of adding mode of reagents,reaction temperature,reaction time and glucose concentration on Cu₂O particles were studied.The results show that the adding mode of reagents has important effect on the dispersibility of Cu₂O particles.The dispersibility of Cu₂O particles is the best when the glucose reduction is carried out after mixing CuSO₄ with NaOH.The average sizes of Cu₂O particles become smaller with increasing temperature.The spherical Cu₂O particles were obtained as a result of aggregation growth mode,and Cu₂O particles average size is 1.42μm to 0.78μm at the range of 40 to 60℃. Mixture of spherical and cubic Cu₂O particles was obtained as a result of the two-dimensional and dislocation growth modes accompanying with a temperature higher than 60℃.Prolonging reaction time slightly affect the morphology and size of Cu₂O particles at the rage of 20min to 120min. The glucose concentration significantly affects the morphology and size of Cu₂O particles.The dominant growth mode of Cu₂O crystal converted from dislocation growth to two-dimensional growth and aggregation growth and the morphology of Cu₂O particles changed from octahedron through similar spherical,mixture of cube and sphere to sphere when glucose concentration changed gradually from 0.25mol/L to 2.0mol/L. The sizes of Cu₂O particles become smaller with increasing the glucose concentration.Spherical Cu₂O particles of 2.71μm to 1.08μm were obtained when glucose concentration changed from 0.4mol/L to 2.0mol/L.Comparing two methods,the constant temperature method has advantages that the condition controlling is simpler and obtained Cu₂O particles are more uniform.更多还原