In drinking water treatment, sand filters are frequently used to remove turbidity. We enhanced the performance of the sand by a chemical modification using graphite oxide (GO). Repeated coating of sand granules with graphite oxide (GO) followed by low temperature (120 °C) pyrolysis yielded hierarchical core-shell structures. The sand granules can be coated with GO in a single (hereafter S-GO1) or multiple (presently five cycles, hereafter S-GO5) coating steps. The GO coated sand composites were characterized using spectroscopic, microscopic, and conventional techniques. When compared to S-GO1, the GO coatings on S-GO5 show enhanced stability in contact with water. The S-GO5 removes over 70% fluoride around pH 6.30 ± 0.02 according to Hill adsorption model. We also used a simulated water sample to assess the efficacy of sand/GO composites to remove fluoride and turbidity. When S-GO5 is used, the solution turbidity has reduced by 87% (from 0.08 to 0.01 NTU). However, in the presence of S-GO1, the turbidity has increased by + 75% (from 0.08 to 0.14 NTU). The gradual dissolution of adhered GO on S-GO1 enhanced the turbidity of treated water. The S-GO5 can be used to regulate excess fluoride and turbidity in water, simultaneously.

在饮用水处理中，经常使用砂滤器去除浑浊。通过使用氧化石墨（GO）进行化学改性，我们提高了沙子的性能。用氧化石墨（GO）重复涂覆砂粒，然后进行低温（120°C）热解，得到分层的核-壳结构。可以在单个（以下为S-GO1）或多个（目前为五个循环，以下为S-GO5）涂覆步骤中用GO涂覆砂粒。使用光谱，显微镜和常规技术对GO涂层砂复合材料进行了表征。与S-GO1相比，S-GO5上的GO涂层在与水接触时表现出更高的稳定性。根据Hill吸附模型，S-GO5去除pH值为6.30±0.02时超过70％的氟化物。我们还使用了模拟水样来评估砂/ GO复合材料去除氟化物和浊度的功效。使用S-GO5时，溶液的浊度降低了87％（从0.08降低到0.01 NTU）。但是，在存在S-GO1的情况下，浊度增加了+ 75％（从0.08 NTU到0.14 NTU）。附着的GO在S-GO1上的逐渐溶解增强了处理水的浊度。S-GO5可用于同时调节水中的过量氟化物和浊度。