Wongsawaeng Doonyapong, Wongjaikham Wijittra, Swantomo Deni, Basuki Kris Tri
Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Department of Nuclear Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand.
Appl Radiat Isot. 2020 Apr;158:109067. doi: 10.1016/j.apradiso.2020.109067. Epub 2020 Jan 31.
An innovative seawater uranium adsorbent was prepared from the low-cost and commercially-available polyacrylonitrile (PAN) fibers. The optimum condition to synthesize the adsorbent was to irradiate the PAN fibers with 100 kGy gamma ray, amidoximate in 3 (w/v)% hydroxylamine hydrochloride solution for 75 min at 75 °C, yielding the PAN nitrile group conversion of approximately 60%. At 100 kGy, the degree of crystallinity of the irradiated fibers was also highest at 79.1%. The performances of the adsorbent in seawater samples were excellent. By submersion in the seawater sample spiked with 250 ppb of uranium for 4 weeks, the prepared fibers exhibited the adsorption capacity of 32.28 mg/g adsorbent. By submersion in seawater samples spiked with 76.5 ppm of uranium for 1 week and 945 ppm of uranium for up to 4 weeks, the fibers exhibited the adsorption capacities of 111.25 and 200.07 mg/g adsorbent, respectively. The adsorbent showed a uranium adsorption capacity of 0.11 mg/g adsorbent for 8 weeks of soaking in brine concentrate from a seawater reverse osmosis plant. The kinetics of seawater absorption by the adsorbent was quite rapid, reaching the equilibrium swelling ratio of approximately 300% in 5 min or less. Another important finding was that the prepared PAN fibers exhibit the characteristics of a superabsorbent material (equilibrium swelling ratio in DI water of 5,550%). The low cost and the ease of preparation of the fibers offer a novel environmental remediation process to adsorb uranium ions released into seawater following a nuclear accident.
一种创新型海水铀吸附剂由低成本且市售可得的聚丙烯腈（PAN）纤维制备而成。合成该吸附剂的最佳条件是用100千戈瑞的伽马射线辐照PAN纤维，在3%（重量/体积）的盐酸羟胺溶液中于75℃肟化75分钟，使得PAN腈基转化率约为60%。在100千戈瑞时，辐照纤维的结晶度也最高，为79.1%。该吸附剂在海水样品中的性能优异。将其浸没在添加了250 ppb铀的海水样品中4周，制备的纤维展现出32.28毫克/克吸附剂的吸附容量。将其浸没在添加了76.5 ppm铀的海水样品中1周以及添加了945 ppm铀的海水样品中长达4周，纤维分别展现出111.25和200.07毫克/克吸附剂的吸附容量。该吸附剂在海水反渗透装置的浓缩盐水中浸泡8周时，铀吸附容量为0.11毫克/克吸附剂。该吸附剂对海水的吸附动力学相当迅速，在5分钟或更短时间内达到约300%的平衡溶胀率。另一个重要发现是，制备的PAN纤维展现出超吸水性材料的特性（在去离子水中的平衡溶胀率为5550%）。这些纤维成本低且易于制备，为吸附核事故后释放到海水中的铀离子提供了一种新型的环境修复方法。
