Application for effective fluoride removal
Fluoride-contaminated drinking water remains a major environmental problem consequent to various ramifications it poses on human and animal health: i.e. skeletal fluorosis and cancer, particularly in rural areas where awareness is low. Therefore, the development of an effective and facile fluoride removal techniques is urgently needed. Adsorption is among the most widely used pollutant removal techniques credit to its low cost and ease of operation. Fluoride can be best adsorbed by rare-earth elements, a characteristic attributable to their high electrical affinities to F–. Despite this knowledge, rare-earth element-based adsorbents are seldom used due to the cost implications they bare. As such, finding methods which can sharply reduce the cost of rare earth-based adsorbents is important for the development and practical application of these highly promising de-fluoridation materials. To this end, considerable attention has been paid to the synthesis of composites, especially tri-metal composites of rare earth-based adsorbents. Such has been the trend as the minimal amounts of rare earths used can significantly offset the manufacturing cost.
In fact, researchers have already reported several tri-metal composites. Previous studies shows that size and shape are important for nanomaterial properties; however, morphology control has not received enough attention in most of these tri-metal adsorbents, as most of the previously reported adsorbents were amorphous. In light of this, it can then be hypothesized that the regular control of the composites’ morphology may be one effective way to improve their adsorption performance. To prove this, researchers from the Nanchang Hangkong University: Tao Wang, Professor Pinghua Chen, Menglin Li, Professor Xubiao Luo, Dr. Lingling Liu, Dr. Guisheng Zeng, Jianyuan Jiang, Keyi Huang, Xueyuan Xu and Professor Hualin Jiang, in collaboration with Professor Songjun Li at the Jiangsu University looked carefully at the morphological effects on fluoride adsorption using a novel La-Zr-Ce tri-metal adsorbent they prepared. Their work is currently published in Journal of Chemical Technology and Biotechnology.
The research team prepared the novel La-Zr-Ce tri-metal adsorbent using a simple technique. The prepared composite had two morphological shapes: i.e. nanoprisms of La2(C2O4)3 decorated with nanospheres of Fe3O4@m(ZrO2-CeO2). The researchers characterized the prepared samples by energy-dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibrating sample magnetometer and X-ray photoelectron spectroscopy.
The authors reported that the nanocomposite had a maximum sorption capacity of 117.3 mg g−1 toward fluoride, which was among the highest ever reported for fluoride adsorbents. Furthermore, it had a wide applicable pH range of 2–10 and high anti-interference ability. In addition, the researchers further elucidated on the different functions of La2(C2O4)3 nanoprisms and Fe3O4@m(ZrO2-CeO2) nanospheres in the composite.
In summary, a novel La-Zr-Ce tri-metal adsorbent with regular morphology was successfully synthesized using step-by-step precipitation methods. Remarkably, the introduction of zirconium in fluoride adsorbent composites was a master stroke as the results were exemplary. In a statement to Advances in Engineering, Professor Hualin Jiang pointed out that their study introduced a facile method that is beneficial for the development of more highly effective adsorbents to treat F− contaminants.
Tao Wang, Pinghua Chen, Menglin Li, Xubiao Luo, Lingling Liu, Guisheng Zeng, Jianyuan Jiang, Keyi Huang, Xueyuan Xu, Songjun Li, Hualin Jiang. Synthesis of La2(C2O4)3 nanoprisms decorated with Fe3O4@m(ZrO2-CeO2) nanospheres and their application for effective fluoride removal. Journal of Chemical Technology and Biotechnology 2019; volume 94: pages 3650–3660.