摘要
赤泥是氧化铝生产过程中所排放的一种强碱性固体废弃物,每年排放量巨大且利用率低,造成了严重的资源浪费和环境污染,如何有效资源化回收利用赤泥是亟须解决的问题。从赤泥的危害、理化性质和综合利用现状出发,对赤泥基吸附剂的应用研究进展进行了详细综述。赤泥粒度细、比表面积和孔隙率较高,含有多种活性成分,适合制备吸附剂以处理含污废水。然而,赤泥若直接应用于污水处理,处理能力有限,并且高碱性的赤泥若直接用于处理污水,会使溶液p H值升高。为此,常采用一系列的活化工艺对赤泥进行活化,制备赤泥基吸附剂。活化工艺不仅可以提高赤泥基吸附剂的吸附性能,还在一定程度上可以预防赤泥造成二次污染。目前常用的赤泥活化工艺主要有酸活化工艺、热活化工艺以及中和活化工艺。酸活化工艺可明显提升赤泥对阴离子的吸附效果;热活化工艺可减少传质阻力、高温造孔并使矿物转化,但成本较高;中和活化赤泥常用于处理金属阳离子。联合活化技术能综合利用单一活化技术的优点,使活化后的赤泥有更好的吸附性能,但联合活化技术操作较为复杂,成本也更高,导致现有的联合活化技术在工业上很难被大规模应用。目前,赤泥基吸附剂已被研究用于处理污水中的非金属阴离子、金属阳离子和有机污染物。列举了赤泥基吸附剂去除废水中的阴离子和重金属阳离子的实例,阐述了其去除机理:赤泥基吸附剂对一些废水中特定的污染物,如PO_(4)^(3-)、F^(-)、AsO_(4)^(3-)等表现出良好的吸附性能,其主要通过表面络合、离子交换和沉淀作用去除废水中的阴离子污染物;经过活化改性后的赤泥能有效去除水中如铅、铜、铬等重金属阳离子,针对不同的目标阳离子,去除机理也有所不同,主要包括离子交换、共沉淀、静电吸引、“阳离子-π”相互作用、络合作用和物理吸附等。但目前对赤泥基吸附剂对各种污染物的去除机理尚未完全明确,且对多种污染物同时存在下的竞争吸附体系研究较少。综上分析指出,在未来赤泥基吸附剂的研究中,寻找便捷、廉价的活化工艺方法制备新型、高效、环保的吸附剂,提高赤泥基吸附剂的吸附性能是一个重要的研究方向。同时,在赤泥基吸附剂的制备和处理废弃物的研究中,应加强制备机理和吸附机理的研究,为赤泥基吸附剂的生产和工业应用提供理论指导。
Red mud is a kind of strong alkaline solid waste discharged in the process of alumina production.The annual emission is huge and the utilization rate is low,which causes serious waste of resources and environmental pollution.How to ef-fectively recycle and utilize red mud is an urgent problem to be solved.Based on the hazard,physical and chemical properties and comprehensive utilization status of red mud,the application research progress of red mud-based adsorbents is reviewed in detail.Red mud has a fine particle size,high specific surface area and porosity,and contains a variety of active ingredients,which is suitable for treating wastewater containing pollution.However,if red mud is directly applied to sewage treatment,its treatment capacity is limited,and if highly alkaline red mud is directly used to treat sewage,the pH value of the solution will increase.Therefore,a series of activation processes are often used to activate red mud to prepare red mud-based adsorbents.The activation process not only improves the adsorption performance of red mud-based adsorbents,but also prevents secondary pol-lution caused by red mud to a certain extent.At present,the commonly used activation process of red mud mainly includes acid activation process,thermal activation process and neutralization activation process.The acid activation process can significantly improve the adsorption effect of red mud on anions.The thermal activation process can reduce the mass transfer resistance,high temperature pore-forming and mineral transformation,but the cost is high.Neutralizing activated red mud is often used to treat metal cations.The combined activation technology can comprehensively utilize the advantages of single activation process men-tioned above,so that the activated red mud has better adsorption performance.However,the combined activation technology has more complicated operation and higher cost,which makes it difficult to be applied on a large scale in industry.At present,red mud-based adsorbents have been studied for the treatment of non-metallic anions,metal cations and organic pollutants in wastewater.In this paper,the examples of removing anions and heavy metal cations in wastewater by red mud-based adsorbents are listed,and the removal mechanism is expounded.Red mud-based adsorbents show good adsorption performance for some specific pollutants in wastewater,such as PO^(3-)_(4),F^(-),AsO^(3-)_(4),etc.,which mainly remove anionic pollutants in wastewater through surface complexation,ion exchange and precipitation.The red mud after activation modification can effectively remove heavy metal cations such as lead,copper,chromium and other heavy metal cations in water.For different target cations,the removal mechanism is also different,mainly including ion exchange,coprecipitation,electrostatic attraction,"cation-π"interaction,complexation and physical adsorption.However,the removal mechanism of various pollutants by red mud-based adsorbents has not been fully clarified,and there are few studies on the competitive adsorption system in the presence of multiple pollutants.In summary,it is pointed out that in the future research of red mud-based adsorbents,it is an important research direction to find a convenient and cheap activation process to prepare new,efficient and environmentally friendly adsorbents and improve the ad-sorption performance of red mud-based adsorbents.At the same time,in the study of the preparation of red mud-based adsor-bents and the treatment of waste,the research on the preparation mechanism and adsorption mechanism should be strengthened to provide theoretical guidance for the production and industrial application of red mud-based adsorbents.
作者
邱俊
杨威
阎正卿
柳晓
吴蓬
化冰冰
QIU Jun;YANG Wei;YAN Zhengqing;LIU Xiao;WU Peng;HUA Bingbing(College of Chemical and Biological Engineering,Shandong University of Science and Technology,Qingdao 266590,China;State Key Laboratory of Mineral Processing Science and Technology,Beijing 100070,China)
出处
《金属矿山》
CAS
北大核心
2024年第2期39-47,共9页
Metal Mine
基金
国家重点研发计划青年科学家项目(编号:2023YFC2909000)
矿物加工科学与技术国家重点实验室开放基金项目(编号:BGRIMMKJSKL-2023-22)
山东科技大学研究生科研创新项目(编号:202182090026)
山东科技大学菁英计划(编号:skr21-3-C-108)
山东科技大学人才引进科研启动基金项目(编号:2017RCJJ036)
青岛西海岸新区2020年度科技项目(编号:2020-2-3)。
关键词
赤泥
资源化利用
吸附剂
废水
red mud
resource utilization
adsorbents
waste water
