Zhang Yangzhong, Huang Kai
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing Xueyuan Rd 30, Haidian District 100083 Beijing China
Beijing Key Lab of Green Recycling and Extraction of Rare and Precious Metals, University of Science and Technology Beijing Xueyuan Rd 30, Haidian District 100083 Beijing China.
RSC Adv. 2019 Mar 8;9(14):7767-7776. doi: 10.1039/c9ra00109c. eCollection 2019 Mar 6.
This study presents a new type of biomass material for defluoridation from water; the material was prepared by loading tetravalent zirconium ions onto grape pomace produced from grape juicing and wine factories. Experiments showed that the optimum pH of defluoridation is around 3.0, and the fluorine removal efficiency could reach 96.13% for one-time contact. In batchwise adsorption tests, it was very interesting to find that even at pH values near 10, at which traditional adsorbents usually do not function for defluoridation, the removal efficiency of fluoride was still more than 90% for the Zr(iv)-loaded grape pomace (Zr(iv)-GP) biosorbent; proton release from Zr(iv)-GP was confirmed to cause an automatic decrease of the pH, which can save additional acid consumption in the case of one-time use and render the defluoridation more convenient and efficient. The maximum adsorption capacity of Zr(iv)-GP was 7.54 mg g; as a comparison, the maximum adsorption capacities of zirconium-loaded strongly acidic ion exchange resin D001 and zirconium-loaded weakly acidic ion exchange resin D113 were evaluated to be 4.85 mg g and 1.14 mg g, respectively. The effects of coexisting anions, such as Cl, NO, SO , CO and HPO , on the fluorine removal efficiency were also examined; it was found that CO and HPO anions had drastically adverse effects on defluoridation, while Cl, NO, and SO appeared not to interfere. Real groundwater containing 1.8 mg L fluoride sampled from Guanzhuang Village in Haixing County of Hebei Province was used for defluoridation through a continuous column adsorption process; it was found that pre-adjusting the groundwater pH affected the purification efficiency drastically, , the time of the breakthrough point for the inlet groundwater pH at 3.0 was about 8 times longer than that at the original pH of 8.18. In addition, the Zr(iv)-GP adsorbent retained good adsorption capacity even after 3 cycles of adsorption-desorption-adsorption operations, indicating that the synthesized zirconium-loaded grape pomace is a very promising new fluorine-removing material for groundwater purification.
本研究提出了一种新型的用于水中除氟的生物质材料；该材料是通过将四价锆离子负载到葡萄榨汁厂和葡萄酒厂产生的葡萄渣上制备而成。实验表明，除氟的最佳pH值约为3.0，一次性接触时氟去除效率可达96.13%。在分批吸附试验中，有趣的是发现即使在pH值接近10时（传统吸附剂通常在此pH值下对除氟不起作用），负载Zr(IV)的葡萄渣（Zr(IV)-GP）生物吸附剂对氟的去除效率仍超过90%；已证实Zr(IV)-GP释放质子会导致pH值自动降低，这在一次性使用的情况下可节省额外的酸消耗，并使除氟更方便、高效。Zr(IV)-GP的最大吸附容量为7.54 mg/g；作为比较，负载锆的强酸性离子交换树脂D001和负载锆的弱酸性离子交换树脂D113的最大吸附容量分别评估为4.85 mg/g和1.14 mg/g。还研究了共存阴离子（如Cl⁻、NO₃⁻、SO₄²⁻、CO₃²⁻和HPO₄²⁻）对氟去除效率的影响；发现CO₃²⁻和HPO₄²⁻阴离子对除氟有严重不利影响，而Cl⁻、NO₃⁻和SO₄²⁻似乎没有干扰。通过连续柱吸附过程，使用从河北省海兴县官庄村采集的含氟量为1.8 mg/L的实际地下水进行除氟；发现预先调节地下水pH值对净化效率有极大影响，进水地下水pH值为3.0时的穿透点时间比原始pH值8.18时的穿透点时间长约8倍。此外，Zr(IV)-GP吸附剂即使在经过3次吸附-解吸-吸附操作循环后仍保持良好的吸附容量，这表明合成的负载锆的葡萄渣是一种非常有前途的用于地下水净化的新型除氟材料。
