锌离子对磷酸铵镁沉淀法回收镁效率影响的研究

以模拟含镁废水为对象,研究了Zn~(2+)浓度及pH对磷酸铵镁沉淀法回收镁效率的影响,并对在不同锌离子浓度、不同pH的条件下所得产物及其产率进行分析比较。实验结果表明,在锌离子、镁离子共存的条件下采用磷酸铵镁沉淀法回收镁,当溶液的pH一定时,随着锌离子浓度的增加,回收镁的效率降低,Zn~(2+)的存在使得生成磷酸铵镁沉淀的反应受到抑制从而影响回收镁效率;在Zn~(2+)浓度一定的条件下,回收镁的效率随着pH的增加先升高后降低,当pH为9.0时回收镁的效率最高。     

磷酸铵镁化学结晶技术研究现状

磷酸铵镁结晶技术因具有资源化回收废水中的氮和磷的特点而受到国内外学者的关注。介绍了磷酸铵镁的结晶机制以及沉氨过程中的影响因素,阐述了磷酸铵镁晶体成核诱导过程,分析了磷酸铵镁结晶过程中pH值、温度、药剂投加比例以及干扰离子对磷酸铵镁的影响,指出了pH值和药剂投加比例是磷酸铵镁结晶过程中最重要的2个影响因素。     

用磷酸铵镁制备废水处理中氨氮吸附剂的研究

化学沉淀法不但去除废水手的氨氮效果较好,而且可以回收再利用氨氮,但因沉淀剂价格昂贵导致处理成本较高。对化学沉淀法所产生的磷酸铵镁焙烧后的产物作为废水处理中氨氮吸附剂进行研究,结果表明,采用磷酸铵镁焙烧回用法可以去除废水中的氨氮。磷酸铵镁的最佳焙烧条件为100℃,2h,在该条件下磷酸铵镁由晶态变为非晶态。当原水的pH为10,焙烧产物用量为2g／L时,吸附30min氨氮去除率可达89．9％。研究表明,氨氮的吸附符合Langmuir吸附等温式。     

废水中磷回收技术的研究进展

详细阐述4种从废水中回收磷的原理及方法的研究现状,包括化学沉淀法、吸附法、生物法、结晶法,分析并比较每种方法的优势与不足,为不同条件下污水中磷的回收提供依据,并展望了今后的研发方向。磷酸铵镁可作为一种环境友好型的缓释肥,磷酸铵镁结晶法的应用将成为从废水中回收磷的一种趋势,将得到更广泛的推广应用。     

磷酸铵镁沉淀法处理氨氮废水的研究进展

本文总结了磷酸铵镁沉淀法的优点和缺点,并针对其缺点以及影响因素从镁源、pH值、投配比、反应时间、反应温度等几个方面介绍了近几年国内外学者的研究进展。此外,介绍了磷酸铵镁联合吹脱法的处理工艺,并展望了磷酸铵镁沉淀法的发展前景以及未来的研究方向。     

磷酸铵镁（MAP）沉淀法处理低浓度氨氮污海水

大量氮磷营养物质排入海湾,引起了富营养化、赤潮等一系列海洋污染问题,污海水中氮磷处理技术研究已引起人们的重视。磷酸铵镁化学沉淀法具有可同时脱除氨氮和磷酸盐,但还未应用于低浓度氨氮废水的处理,尤其是污海水中氨氮的处理。本文采用磷酸铵镁（MAP）化学沉淀法对污海水中氨氮进行处理实验研究,利用污海水中大量存在的Mg2+,以Na2HPO4作为沉淀剂,探讨了初始反应体系pH值、PO43?/NH4+投配比、反应时间等因素对氨氮脱除效果的影响。结合沉淀结晶物XRD和SEM分析,确定了MAP沉淀法处理污海水中氨氮的最佳反应条件：初始反应体系pH值为9.5～10.5,PO43?/NH4+投配比为1.1/1,反应时间为40 min。实验结果表明,在最佳反应条件下,随着氨氮初始浓度的增大,氨氮去除率逐渐增大,当进水氨氮浓度为12 mg/L时,氨氮去除率达到42.80%。     

磷酸铵镁沉淀法处理草甘膦母液中氨氮的研究

以某化工厂草甘膦母液为研究对象,采用磷酸铵镁沉淀法去除废水中的氨氮,同时合成磷酸铵镁晶体。本文通过研究反应比、pH等因素确定了磷酸铵镁沉淀法处理的最佳反应条件。结果表明磷酸铵镁沉淀法适用于处理含高浓度氨氮废水,最佳反应比为n(Mg⁽²⁺⁾)∶n(NH_4(2+))∶n(NH_4⁺)=1.6∶1,最佳反应pH值为10。在最佳反应条件下,氨氮去除率可达97%。     

磷酸铵镁沉淀法回收污泥浓缩液中磷的实验研究

利用磷酸铵镁沉淀法收集污泥浓缩液中磷，考察了pH值、搅拌强度、反应时间对磷回收率的影响，结果表明，污泥浓缩液中■，有利于用磷酸铵镁沉淀法回收磷，在pH值为9、搅拌速度为40r·min^-1、反应时间为20min的条件下可使磷回收率达到90%以上，此时Mg NH₄PO₄·6H₂O纯度也较好，废水处理成本也相对合理。     

磷酸铵镁法处理污水回收氮磷影响因素的研究

介绍了磷酸铵镁(MAP)法回收氮磷基本原理、影响因素。提出选择本法首先要考虑污水适合资源化回收氮磷;其次,沉淀剂添加量既要考虑MAP结晶效果好纯度高,又要兼顾不会给后续处理增加盐分等负担,避免二次污染;再有,努力研发海水、高Mg水(污水)等高效廉价沉淀剂。     

磷酸铵镁结晶技术与肥料化利用

概述了磷酸铵镁结晶技术回收废水中氮、磷的基本原理与影响因素,分析了磷酸铵镁产品特性和磷素养分释放特征,并推荐磷酸铵镁在缓释肥和酸性土壤调理剂方面的应用,以期为我国废弃物资源肥料化利用提供参考。     

Reducing ammonia emission from poultry manure composting via struvite formation

Composting can provide a viable alternative for poultry manure management in the Fraser Valley of British Columbia, Canada. However, it has a high potential for ammonia emission because of the high nitrogen content of poultry litter. The objective of this study was to reduce ammonia emission by precipitating ammonia into struvite before it can volatilize from the composting matrix. Nitrogen transformation occurs during composting, but struvite formation can help to conserve nitrogen, and does not allow a large amount of nitrogen to be released into the environment as ammonia or nitrate, because ammonium‐nitrogen becomes bound in struvite. It would also be possible to remove phosphorus from the manure. A laboratory‐scale experiment was conducted to examine the feasibility of struvite formation during poultry manure composting. Magnesium and phosphate salts were supplemented to create favorable conditions to form struvite. Results indicated that ammonia emission was reduced by 40% to 84%, while the nitrogen retention in compost was enhanced. The struvite formed in compost was confirmed by means of X‐ray diffraction; and scanning electron microscopy with energy dispersive X‐ray spectroscopy. Copyright © 2007 Society of Chemical Industry     

污水磷回收中磷酸盐沉淀法的影响因素及应用

磷是一种不可再生、十分有限的资源,它的回收再利用已成为水处理工业关注的焦点.污水中的磷可以以磷酸盐沉淀的形式回收,其中以鸟粪石和磷酸钙的形式从污水中回收磷被认为是最具有前景的磷回收途径.作者对生成鸟粪石和磷酸钙的主要影响因素及鸟粪石和磷酸钙沉淀法在污水磷回收中的应用作了全面的概述,并对存在的问题作了简要分析.     

鸟粪石添加剂对准东煤燃烧过程中钠、钙矿物转化和释放的影响

准东煤作为优质动力煤,高含量的Na和Ca导致沾污结渣成为制约其大范围工业应用的因素。选取准东五彩湾煤作为研究对象,使用富磷鸟粪石作为添加剂,分别对500℃下处理后的原煤灰和混合煤灰（掺入质量分数为5%的鸟粪石）进行同步热分析;在管式炉中以空气气氛对原煤和混合煤在不同温度下进行燃烧实验;通过 X射线荧光光谱分析仪（XRF）、X射线衍射分析仪（XRD）、电感耦合等离子体发射光谱仪（ICP-OES）对收集灰分进行分析;并通过热力学软件FactSage对实验结果加以验证。结果表明：鸟粪石添加剂对Na和Ca的释放规律影响较大,大量的Na和Ca在燃烧过程中以磷酸复盐的形式聚集在混合煤灰中,Ca的低温共熔物未能生成;在1000℃之前鸟粪石添加剂对Na和Ca的捕集效果较好,温度上升后有所下降。     

廉价氧化镁回收废水中氨氮

药剂成本过高是阻碍磷酸铵镁结晶技术推广应用的关键难题之一。通过改变结晶反应的初始条件,采用廉价氧化镁为镁盐,有效回收废水中的氨氮。研究结果表明,起始pH为2时,氧化镁为镁盐时,废水氨氮去除效率达到90%以上;采用Mg²⁺:NH₄⁺:PO₄^3- 摩尔比为1:1:1,煅烧温度在200～400℃时,氨氮回收率超过82%;XRD和FTIR分析结果表明,不同温度条件下,氧化镁的晶体结构出现畸变,导致Mg O键键长出现变化,红外光谱出现红移及蓝移现象,而Mg O键键长的变化与沉氨效率存在直接的相关性。     

Phosphorus removal and recovery from wastewater by highly efficient struvite crystallization in an improved fluidized bed reactor

Phosphorus is the crucial factor causing eutrophication in the aquatic ecology. The high phosphorus loading in water bodies may result from the direct disposal of untreated wastewater. In this study, a fluidized bed reactor (FBR) was specially developed to remove and recover phosphorus effectively and efficiently via struvite crystallization. Different physiochemical and hydraulic conditions, including hydraulic retention time (HRT), pH, and molar ratios of Mg : P, N : P and Ca : Mg, were explored to optimize the performance of this improved FBR. For the continuous operating trials, promising removal and recovery efficiencies were achieved at the phosphorus concentration of 25.0 mg/L: >90% of phosphorus could be removed under the optimum condition (pH=9, HRT=12 h, Mg : P=1.25 and N : P=7.5). Increasing the recycle flow rate and prolonging the contact time could also enhance the FBR efficiency. The crystal products obtained in FBR were analyzed in terms of composition and structure. Results indicated that almost pure struvite (>99%) was achieved at low calcium concentrations, which could be considered as a high quality fertilizer.     

鸟粪石除磷工艺研究进展

介绍了国内外鸟粪石除磷工艺的研究现状、工艺控制因素及经济实用性,表明了该工艺可以在高效去除污水中磷的同时生成鸟粪石(磷酸氨镁,MAP)——一种优质肥料,同时对今后该工艺的发展前景与研究的方向提出展望。     

高含磷制药废水处理试验研究

以台州某药业公司高磷废水为研究对象,分别采用CaCl2沉淀法和鸟粪石结晶法对其进行试验研究.探讨了CaCl2投加量和pH值对废水中总磷去除率的影响,并在此基础上研究了pH值、n(N)∶n(P)、n(Mg)∶n(P)对鸟粪石生成的影响.试验结果表明,在水样进水总磷的质量浓度(以P计)为374.50 mg/L,pH值为10...     

磷酸镁水泥耐水性的影响因素与改进措施

镁水泥(MPC)是一种新型的早强快硬胶凝材料,可作为修补材料应用于工程修补.从磷酸镁水泥的水化机理出发,讨论磷酸镁水泥主要水化产物鸟粪石( MgNH4PO4·6H2O)的性质、形成及影响因素,及其与磷酸镁水泥耐水性的关系.从理论上提出了通过选择合适活性、粒度和低CaO含量的原材料、优化配合比、控制体系pH值和掺加粉煤灰...     

A fed-batch design approach of struvite system in controlled supersaturation

This paper focuses on struvite (MgNH₄PO₄·6H₂O) crystallization in controlled supersaturation. Struvite can be used as a slow-release fertilizer. Crystallization experiments were conducted using supersaturated solutions. The secondary focus of this paper is the design of a struvite recovery system in fed-batch-controlled supersaturation mode. The design and commissioning of fed-batch struvite crystallization included the determination of operating supersaturation of struvite crystallization, suitable seed materials and the composition of feed solution. Determination of operating supersaturation of struvite crystallization was conducted by two steps including thermodynamic simulation using gPROMS² (process simulation software) along with a set of batch experiments. Investigation of suitable seed materials was also conducted using set of batch experiments. Two types of seed materials including quartz sand and struvite seeds were used in the investigation of seed materials. Composition of feed solution included the investigation of struvite solution chemistry using PHREEQC³ thermodynamic modeling package. Based on the previously investigated design approach, struvite crystallization in fed-batch system was conducted using a 44-L of reactor with 15-L of initial reactant volume.