Controllable synthesis and characterization of high purity calcium carbonate whisker-like fibers by electrochemical cathodic reduction method

Abstract

Although the electrochemical method has been certificated as a promising way for the synthesis of calcium carbonate whiskers, researches on the controllability and efficiency are ignored. In this work, the electrochemical synthesis of calcium carbonate whiskers was studied to evaluate its controllability and efficiency. Micrograph and X-ray diffraction analysis results indicated calcium carbonate whiskers was successfully synthesized with a high production of 94.59% by using electrochemical method to stimulate cathodic reaction in calcium-containing solution. Length and aspect ratio of whisker can be controlled by regulating nucleation and growth conditions. The optimal conditions for whiskers synthesis were nucleating 5 min at 18 V and growing 55 min at 2 V in the solution containing 600 mg/L of calcium chloride, 300 mg/L of sodium bicarbonate, and 150 mg/L of magnesium chloride with a constant temperature of 70 °C. The calcium carbonate whisker has an 18.78 μm whisker length and 36.82 aspect ratio. The product morphology depended on the uniformity of carbonate and the presence of magnesium. The uniform distribution of the generated CO 3 2− was responsible for producing CaCO 3 whiskers. Besides, presence of magnesium can avoid of hydroxide overproduction and regulate supersaturation of CaCO 3 during synthesis to control the one-dimensional growth of whiskers. This work demonstrated the potential of controllable and efficient synthesis of calcium carbonate whiskers using electrochemical method. • Synthesize calcium carbonate whiskers with aspect ratio of 36.82 on stainless-steel cathode. • Whiskers length and aspect ratio were controlled through regulating nucleation voltage and reaction temperature. • Whiskers morphology depended on the uniformity of carbonate and the presence of magnesium. • Colloidal precipitate of Mg(OH) 2 promoted the one-dimensional growth of calcium carbonate crystals.