Bio-Template Synthesis of Strontium Titanate and Application for Heavy Metal Adsorption in Wastewater

Abstract

Heavy metal ions, such as chromium, cadmium, mercury, nickel, copper, and zinc, cause severe pollution to water bodies as well as enormous harm to people and the biosphere. Adsorption and removal of heavy metal pollution in water is a low-cost and straightforward method. Researchers are currently looking for materials that are cheap and readily available, and have high adsorption and enrichment properties for heavy metal ions. Strontium titanate is a new type of ceramic material, and there have been few related research reports. The work reported a new method for the synthesis of strontium titanate adsorbent by the sol-gel biotemplate method. A sol-gel method, using different types of straws as biological templates, was selected to prepare nano-strontium titanate adsorption materials. In this experiment, chelate formed using tetra-n-butyl titanate and strontium nitrate as raw materials, and acetic acid as a chelating agent, thereby forming a sol. Then, corn straw and sunflower straw immersed in the sol and aged for a period. After drying and calcination, a strontium titanate adsorbent with a biofilm microstructure was obtained. Besides, the structure of strontium titanate synthesized was characterized by SEM and XRD. In this experiment, zinc ions were used as adsorbed ions to investigate the adsorption capacity of the synthesized strontium titanate adsorbents for heavy metal ions in water. Studies have shown that strontium titanate synthesized by the biological template method was a porous material retaining some of the natural tissue structure characteristics of the biological template. Compared with the strontium titanate obtained without using the biological template, the adsorption capacity of the strontium titanate powder synthesized by the biological template method to zinc ion was significantly improved. We studied the influence of the selection and adsorption of biological templates and pH conditions on the ability of strontium titanate to adsorb zinc ions.