Researches on the Treatment of Phosphorous Wastewater with Oyster Shells

Based on the analysis of adsorptive features of oyster shells,the researches on the treatment of phosphorous wastewater with oyster shells and the effect of temperature on phosphorus removal were carried out.XRD was used to characterize the crystalline phases,and the main component of oyster shells was shown to be CaCO3.When the pretreatment temperature reached 800 ℃,some CaCO3 decomposed into CaO.As the temperature was further raised,CaO increased gradually.Via SEM testing,the oyster shell was a kind of natural porous materials.The pore wall partially collapsed from 550 to 900 ℃.No obvious porous structure was found at 900 ℃.However,without preheating,the oyster shell phosphorous removal material can not adsorb the phosphorus.Pretreatment made calcium activate,thus greatly increasing the absorption of phosphorus.

A Study on the Structure and Behavior of Sinter-free Material for Phosphorous Removal from Waste Water

Oyster shell and cement were taken as the major raw materials to fabricate hollow, tubular and recoverable material for phosphorous removal （P removal） from waste water without sintering. In this paper, the effects of different affecting factors on the sample P removal ratio were discussed to select optimal P removal process conditions. SEM and XRD were used to characterize the microscopic structures and composition of samples, and molybdenum blue spectrophotometry was applied to determine the P content in waste water. Results showed that at 30 ℃ for 2 d, the P removal ratio reached 93.3% when the cement content was 10 wt% and oyster shell powder was 90 wt%. SEM analysis revealed a flaky structure consisting of phosphorus-containing compound in the samples after P removal, and it piled on and maintained the porous structure. In addition, the results also suggested that raising the ambient temperature was benefit to the P removal. The P removal ratio of the material was optimal under neutral and alkali conditions.

Genetic Toxic Effects of Rare-earth Waste and Its Products on Peacock Fish

The micro-nuclei and abnormal nuclei rates of peacock fish are tested,genetic toxic effects of rare-earth waste and its products(cement,plastic) on peacock in water are investigated.Results show that the leachate of rare-earth waste can lead to micronuclei and abnormal nuclei rates of peacock fish an obvious increase(P<0.01). Products made of the waste cause the micronuclei rate to be increased because of its low radio active action,but the change in abnormal nuclei rate can't reach a remarkable level.It shows that rare-earth waste has a certain effect of causing mutation on aquatic organism.Harmfulness of products made from this waste is decreased largely,and resources can be effectively saved.

Mechanochemical-Assisted Leaching of Lamp Phosphors： A Green Engineering Approach for Rare-Earth Recovery

Rare-earth elements （REEs） are essential metals for the design and development of sustainable energy applications, Recycling these elements from waste streams enriched in them is crucial for securing an independent future supply for sustainable applications, This study compares the mechanisms of mechan- ical activation prior to a hydrometallurgical acid-leaching process and a solvometallurgical mechanochemical leaching process for the recovery of REEs from green lamp phosphor, LaPO4：Ce3＋, Th3＋, After 60 min of processing time, the REE leaching rates showed a significant enhancement of 60% after cycled mechanical activation, and 98% after the combined mechanochemical leaching process, High-resolution transmission electron microscopy （HR-TEM） imaging disclosed the cause for the improved REE leaching rates： The improved leaching and leaching patterns could he attributed to changes in the crystal morphology from monocrystalline to polycrystalline, Reduction of the crystallite size to the nanoscale in a polycrystalline material creates irregular packing of chemical units, resulting in an increase in defect-rich grain boundaries in the crystals, which enhances the leaching process, A solvometallurgical method was developed to combine the mechanical activation and leaching process into a single step, which is beneficial for operational cost, This results in an efficient and simple process that provides an alternative and greener recycling route for lamp phosphor waste,

Isolation of Thermally Stable Cellulose Nanocrystals from Spent Coffee Grounds via Phosphoric Acid Hydrolysis

As the world's population exponentially grows,so does the need for the production of food,with cereal production growing annually from an estimated 1.0 billion to 2.5 billion tons within the last few decades.This rapid growth in food production results in an ever increasing amount of agricultural wastes,of which already occupies nearly 50%of the total landfill area.For example,is the billions of dry tons of cellulose-containing spent coffee grounds disposed in landfills annually.This paper seeks to provide a method for isolating cellulose nanocrystals(CNCs)from spent coffee grounds,in order to recycle and utilize the cellulosic waste material which would otherwise have no applications.CNCs have already been shown to have vast applications in the polymer engineering field,mainly utilized for their high strength to weight ratio for reinforcement of polymer-based nanocomposites.A successful method of purifying and hydrolyzing the spent coffee grounds in order to isolate usable CNCs was established.The CNCs were then characterized using current techniques to determine important chemical and physical properties.A few crucial properties determined were aspect ratio of 12±3,crystallinity of 74.2%,surface charge density of(48.4±6.2)mM/kg cellulose,and the ability to successfully reinforce a polymer based nanocomposite.These characteristics compare well to other literature data and common commercial sources of CNCs.

溶剂萃取法自铝材抛光废液中分离去除硫酸及其机理的研究

研究了利用溶剂萃取体系自铝材抛光废液中分离去除硫酸并纯化提取磷酸的工艺。系统考察三烷基胺(N235)浓度、萃取温度、相比、振荡时间等因素对萃取率的影响,并用McCabe-Thiele图解法预测理论阶段数,结果表明在相比为O/A=2的三个理论阶段后,98%以上的H_(2)SO_(4)将被去除。设计了一系列串级实验进行三级逆流萃取模拟,得到H_(2)SO_(4)的萃取率为95.40%,H_(3)PO_(4)的萃取率仅为3.33%。结果表明该体系对硫酸具有较高选择性,可实现H_(3)PO_(4)与H_(2)SO_(4)的高效分离。通过机理研究可知,萃取配合物以H_(2)SO_(4)·2[N235]形式存在,H_(2)SO_(4)通过与N235形成离子对络合物被萃取进入有机相中。

从废旧稀土荧光粉中回收稀土元素研究进展

稀土荧光粉发光效率高、化学稳定性好、发光亮度强,被广泛用于稀土荧光灯中,而荧光灯有一定的使用寿命,其含有大量的稀土元素以及对环境危害的有毒金属,如果不加以回收与利用,势必会对环境和人体健康造成危害。阐述了从废旧稀土荧光粉中回收稀土元素的方法,分析了浮选法、吸附法、机械活化法和微波浸取法等物理法的工艺现状,详细阐述了萃取法、酸浸法、碱熔焙烧法、生物法等化学法的研究现状和潜在问题,并进一步比较不同稀土回收工艺的优缺点。展望了废旧荧光粉中稀土回收利用技术的未来发展,为提高废旧稀土荧光粉资源利用率提供指导。

磷酸三丁酯脱色活性炭热解再生研究

以磷酸三丁酯(TBP)脱色后的粉末废活性炭(WAC)为材料,利用高温热解的方法,以亚甲基蓝吸附量和碘值为评价指标,研究了再生温度、再生时间、再生次数对废活性炭再生效果的影响。实验结果表明,WAC的再生最优条件为500℃下再生90 min,再生4次仍能恢复其82%的亚甲基蓝吸附性能及67%的碘吸附性能。通过同步热分析仪(TG-DSC)测定活性炭的失重、吸热和放热情况;借助比表面积及孔径分析仪、傅里叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)等测试手段对再生前后的活性炭进行表征,从而验证其再生效果。对废活性炭的热解机理进行了综合分析,为湿法磷酸净化工艺流程中磷酸三丁酯脱色活性炭的热解再生提供了理论指导。

Effects of mechanical activation on the kinetics of terbium leaching from waste phosphors using hydrochloric acid

The effect of mechanical activation （MA） on the kinetics of terbium （Tb） leaching from waste phosphors using hydrochloric acid was investigated. Leaching kinetics, such as apparent reaction rate, activation energy and reaction order, were determined using the shrinking-core model and the Arrhenius equation. Results obtained from experiments with different concentrations of HC1 and under different leaching temperatures were used for the determinations. The impacts of factors such as rotational speed, HC1 concen- tration and leaching temperature on the leaching rate of Tb were also discussed. The results showed that MA could dramatically increase the leaching rate of Tb from waste phosphors, and the apparent reaction rate （kap） of leaching was accelerated as well. For inactivated waste phosphors, the apparent activation energy （Eap） was 52.82±3.95 kJ/mol, indicating that the rate-controlling step of the leaching process was the chemical reaction. The Eap dropped to 25.96 ±3.90 kJ/mol and 10.96±2.79 k J/tool when the waste phosphors were mechanically activated at rotational speeds of 400 and 600 r/min, respectively; the leaching process transformed to a hybrid （chemical-reaction and diffusion） control process, and even a reagent-diffusion （through the product layer） control process. The apparent reaction order for Tb leaching from 400 r/min-activated waste phosphors was 2.49±0.11, and it decreased to 1. 16±0.17 when the rotational speed of 600 r/min was used. Kinetics results indicated that MA could make Tb leaching occur spontaneously, and thc activation intensity of waste phosphors was strengthened with higher rotational speed.

Potential application of graphene oxide and Aspergillus niger spores with high adsorption capacity for recovery of europium from red phosphor,compact fluorescent lamp and simulated radioactive waste

The recovery of rare earth elements(REEs) is a global challenge and the mining of rare earths has serious environmental implications due to the toxic waste released post mining.Hence,the rising demand for rare earths and their far reaching electronic applications necessitates an effective strategy to recover the REEs from more viable sources.In this work,the graphene oxide-Aspergillus niger spores(GO-A.niger spores) blend was utilized for adsorptive recovery of a precious rare earth Eu(Ⅲ) and the adsorption variables like pH of the medium,adsorbent dosage,sorption kinetics,thermodynamics,and isotherm were optimized for the developed bioso rbent.The adsorption process suits the Langmuir isotherm model with a maximum adsorption capacity of 147.3 mg/g.The pseudo-second-order kinetics is a perfect fit to describe the adsorption process.The results obtained through the Van’t Hoff plot show negative free energy change(ΔG^(0)) which implies the spontaneity of the adsorption process.The negative standard enthalpy change(ΔH^(0)) values show that the nature of the adsorption process is exothermic.The analytical characterizations including Fourier transform infrared spectroscopy(FTIR),Raman,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Brunauer-Emmett-Teller(BET),thermal gravimetric analysis(TGA),and scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDX) were employed to study the biosorbent.The features of GO-A.niger spores biosorbent were applied to recover Eu(Ⅲ) from real samples such as fluorescent lamp phosphor,red phosphor powder,and a simulated radioactive waste solution.

工业固废磷石膏综合治理现状及对策

概述了磷石膏的组成、性质,以及在不同湿法磷酸生产工艺下形成的结晶形态。提出了控制磷石膏产量、进行杂质无害化处理,以及磷石膏及其杂质的综合利用等策略。强调了在磷酸生产工艺中优化参数以减少磷石膏产生的重要性,以及通过多种除杂技术提高磷石膏的纯度和利用价值。需要进一步的研究和规划,以实现磷石膏的减量化、无害化和资源化,促进磷化工产业的可持续发展。

废磷酸脱铝技术的研究进展

磷酸是一种重要的化工原料,常用于铝的化学抛光处理以及铝合金等金属的表面处理。铝离子在溶液中不断积累,进而改变化学抛光液的组成和性质,并形成含铝废磷酸。磷酸也用于蚀刻铝制零部件的铝箔层和显示面板的铝层以溶解氧化铝,因此也会产生含铝废磷酸。随着磷资源的不断消耗,未来获取磷酸资源面临严峻挑战。基于环境保护的迫切要求,必须脱除废磷酸中的铝离子,以便更好地回收和利用磷酸资源。本文介绍了去除废磷酸中铝离子的方法,分析了这些方法的利弊,并对未来废磷酸脱除铝离子的研究方向进行了展望。

易流型辅助胶凝材料的制备及其对混凝土性能的影响

基于四川地区的锂渣、钛矿渣、磷渣3种固体废弃物,开展固废基易流型混凝土掺合料的研究。通过与各种掺合料多元体系复配获得了性能优异的易流型掺合料,并系统研究了该辅助胶凝材料对混凝土工作性能、力学性能及耐久性能的影响。结果表明,磷渣粉、钛矿渣粉和石灰石粉复掺替代粉煤灰时,混凝土浆体的屈服应力有小幅下降,扩展度普遍大于550 mm,工作性能得到优化;改性锂渣粉、钛矿渣粉和石灰石粉复掺替代矿粉时,在锂渣粉掺量不高时,混凝土工作性能和力学性能较优,但锂渣粉掺量过大时会增大混凝土塑性黏度,掺量建议不超过胶凝材料的10%。

磷酸吸氨法生产氨水和磷酸铵的可行性研究

在我国焦化行业,磷酸吸氨法生产氨水存在磷氨资源浪费、设备管道易结垢堵塞、磷酸铵溶液处置不够环保等问题。介绍了磷酸吸氨法生产氨水的工艺原理及优缺点,研究了利用高浓度磷酸吸收氨废气后,用于生产高端水溶性、工业级磷酸铵产品的可行性,并提出相应的技改措施和建议。

磷酸法替代硫酸法处理含氨废气的可行性研究及建议

介绍了硫酸法和磷酸法处理含氨废气的技术原理和工艺流程,其中硫酸法是以硫酸为脱除剂,在饱和器或酸洗塔内洗涤吸收氨后生产硫酸铵;磷酸法是以磷酸为脱除剂,在吸收塔内与氨反应生成磷酸一铵,再继续吸收氨生成磷酸二铵,磷酸二铵在解吸塔内解吸出氨后,又转化为磷酸一铵返回吸收塔循环套用,解吸出的氨经冷凝生产氨水。分析评价了二者的经济性、安全性和环保性,得出磷酸法优于硫酸法的结论;从原料、工艺和设备等三方面的适应性,探讨了用磷酸法替代硫酸法处理含氨废气的可行性,并提出了相应的技改措施及建议。

从阳极氧化废磷酸中回收磷资源工艺研究

以阳极氧化废磷酸为原料,与羟基氧化铁反应回收磷得到磷酸铁,通过单因素变量优化实验确定最佳生产条件。实验结果表明:阳极氧化废磷酸稀释到磷酸质量分数为8.00%,按照磷铁物质的量比1.0∶1.1加入羟基氧化铁,反应温度为95℃,反应2 h,磷酸回收率达到95.99%,回收的磷酸铁可用作其他高价值产品原料。

钢渣对废水中磷的去除

介绍了固体废弃物———钢渣处理模拟含磷废水的试验情况 ,试验结果表明 ,钢渣对废水中的磷有明显的去除效果。当废水中磷浓度为 10mg/L ,pH =7.5 0～ 7.6 0、钢渣的用量 0 .5g/ 10 0mL时 ,在 1h内就可使残留液浓度降低到 0 .1mg/L以下 ,远远低于国家排放标准 ,去除率达到 99%以上。对水体富营养化处理具有很重要的意义。

磷酸铵镁法回收稀土分离废水中镁及氨氮的研究

磷酸铵镁法是一种有效的回收氨氮、磷和镁的方法。本文通过热力学计算,分析了反应过程及pH值对磷酸铵镁生成的影响规律。根据理论分析结果,进行了pH值、磷源、加料方式等因素对氨氮、磷去除率的影响实验。结果表明:以Na3PO4为磷源,通过向氮磷混合液中加入含镁废水,并控制反应液pH值为9时,氮磷镁去除率均可达98%以上,得到沉淀物经X衍射分析为六水磷酸铵镁。

热法磷酸燃烧塔内传热特性的工程计算方法

在对热法磷酸燃烧塔进行余热利用的技术改造过程中，迫切需要了解燃烧塔内的传热特性，并准确地计算出塔内的换热量．本文分析了热法磷酸燃烧塔内的传热特性及其影响因素，提出了热法磷酸燃烧塔内传热特性的工程计算方法，由此可以获得余热回收换热量的计算公式．本文对某燃烧塔进行了实际计算，所获得的磷酸余热回收换热量与实验值的比较，误差在１０％以内，满足工程计算的精度要求。这不仅为热法磷酸的余热利用提供了理论指导，而且在实际的磷燃烧塔余热利用的技术改造过程中也具有很强的工程应用价值．

HRT和曝气量对AAO-BAF系统反硝化除磷性能的影响

以COD/TN为4左右的生活污水为处理对象,通过调节系统进水流量和曝气生物滤池(BAF)曝气量,研究了水力停留时间(HRT)和BAF气水比对AAO-BAF反硝化除磷系统运行性能的影响。结果表明,气水比和水力负荷(HLR)对BAF的硝化性能有显著影响,BAF气水比为3:1时,NH+4去除率降低到了72%;当AAO的HRT为4 h,BAF的HLR为3 m3·m-2·h-1时,即使BAF的气水比达到8:1,也不能保证NH+4的完全去除。试验得出,AAO-BAF反硝化除磷系统的PO43-去除率与NH+4去除率存在良好的相关关系,为保证90%以上的磷去除率,NH+4去除率应该达到98%。当AAO的HRT≥6 h,BAF气水比≥4:1时,AAO-BAF系统对COD、NH+4、TN和PO43-的去除率分别可达87%、99%、80%和95%。