CAJ | 학술논문

针对含低水平放射性过渡金属离子废水的处理需求,本工作以 Co(Ⅱ)为代表,研究了粉煤灰衍生介孔硅钙材料对Co(Ⅱ)的吸附去除性能。研究结果表明,高铝粉煤灰“预脱硅-碱石灰烧结提铝”工艺在预脱硅阶段产生的硅钙材料副产品,以水化硅酸钙(C—S—H(Ⅰ))(钙硅原子摩尔比n(Ca)/n(Si)=0.98~1.00)为主要矿相,属于具有高比表面积(733 m2/g)且孔隙发达的介孔材料,同时,其具有良好的酸碱缓冲性能(pH=2~10)以及一定的阳离子交换性能(Ca2+/H+)。介孔硅钙材料在35~60℃对 Co(Ⅱ)吸附容量最高可达209~296 mg/g,整个过程符合 Langmuir单分子层化学吸附,为吸热反应,吸附可在3 h 内快速达到平衡,吸附机理主要为离子交换(占84.5%)。而对实际核电站大修废水的吸附试验结果表明,对其中的放射性Co(Ⅱ)去除率大于98.6%,并且其他放射性过渡金属离子也得到去除。在当前放射性核素的水泥固化处置中,介孔硅钙材料不仅与水泥有较高的相容性从而实现放射性核素的高效稳定化,同时还可替代部分水泥从而实现固化产物的减量化,具有较好的环境和经济效益,因此,该介孔硅钙材料在放射性废水核素去除方面具有较大的资源化应用潜力。
침대함저수평방사성과도금속리자폐수적처리수구,본공작이 Co(Ⅱ)위대표,연구료분매회연생개공규개재료대Co(Ⅱ)적흡부거제성능。연구결과표명,고려분매회“예탈규-감석회소결제려”공예재예탈규계단산생적규개재료부산품,이수화규산개(C—S—H(Ⅰ))(개규원자마이비n(Ca)/n(Si)=0.98~1.00)위주요광상,속우구유고비표면적(733 m2/g)차공극발체적개공재료,동시,기구유량호적산감완충성능(pH=2~10)이급일정적양리자교환성능(Ca2+/H+)。개공규개재료재35~60℃대 Co(Ⅱ)흡부용량최고가체209~296 mg/g,정개과정부합 Langmuir단분자층화학흡부,위흡열반응,흡부가재3 h 내쾌속체도평형,흡부궤리주요위리자교환(점84.5%)。이대실제핵전참대수폐수적흡부시험결과표명,대기중적방사성Co(Ⅱ)거제솔대우98.6%,병차기타방사성과도금속리자야득도거제。재당전방사성핵소적수니고화처치중,개공규개재료불부여수니유교고적상용성종이실현방사성핵소적고효은정화,동시환가체대부분수니종이실현고화산물적감양화,구유교호적배경화경제효익,인차,해개공규개재료재방사성폐수핵소거제방면구유교대적자원화응용잠력。
To meet the needs of treatment of waste water containing low-level radioactive transition metal ions,using Co (Ⅱ)as a representative,the sorption ability of Co (Ⅱ)on calcium-silicate material,which is produced at the pre-desilication stage during the alumina extraction from the high-alumina fly ash by pre-desilication-soda-lime sintering technique,was studied.The results indicate that the calcium-silicate material,with hydration calcium silicate (C—S—H(Ⅰ))as the main mineral,is one of those mesoporous materials with high specific surface area(733 m2/g)and developed void space structure.The material also has good acid and alkali buffer performance(pH=2-10)and cation exchange capacity(Ca2+/H+).The adsorption capacity can reach 209-296 mg/g in the temperature range of 35-60 ℃for Co(Ⅱ).The adsorption process is endothermic and consistent with Langmuir monolayer chemical adsorption.The adsorption equilibrium can be reached quickly within 3 h.Our results show that the main adsorption mechanism is most ion exchange(84.5%).Moreover, the adsorption results for nuclear power plant overhaul wastewater show that more than 98.6% of the radioactive cobalt as well as other radioactive transition metal ions are removed.Speaking from the perspective of practical application,the mesoporous calcium-silicate material not only has high compatibility with cement which is good to the radionu-clide stabilization,but also can replace part of cement to achieve the reduction of the radioac-tive solidification blocks.Because of the above mentioned environmental and economic bene-fits,the mesoporous calcium-silicate material evidently has potential application in radioac-tive transition nuclide removal of wastewater.