Prediction and verification of precipitate formation in the coating wastewater under different pH

doi:10.16085/j.issn.1000-6613.2018-0655

Abstract

Abstract: The coating wastewater was treated by neutralization and precipitation. Removal effect of negative ions such as total phosphorus, sulfate radical and positive ions such as total iron, total lead and total chromium in the coating wastewater was studied under different pH (4-12). The mechanism of precipitation formation during the process of pH adjustment was discussed by using the modified Gibbs function of thermodynamic equation △G=RTln(Q_c/K°_sp). The results showed that when pH value was 2.18-10, the ionic strength (I) was around 0.10mol/L. When pH was 12, the ionic strength (I) was 0.59mol/L. When considering the influence of ionic strength I, the active equilibrium constant K°_sp can be up to 15 orders of magnitude compared with that of the solubility product K_sp. The Gibbis function calculation should be performed by the active equilibrium constant K°_sp. pH had a great influence on the concentration of various forms of existence of weak acid and alkali. When pH=4-8, the precipitates formed were mainly phosphate. When pH=10-12, the types of hydroxide precipitate increased. At pH=12, the precipitates were the most abundant.

Key words: the coating wastewater, thermodynamic equation, formation of precipitate, simulation and prediction

摘要： 采用中和沉淀法处理涂装废水，在不同pH（4~12）下研究了涂装废水中总磷、硫酸根等阴离子和总铁、总铅、总铬等主要的阳离子去除效果，并利用修正后的热力学方程Gibbs函数△G=RTln（Q_c/K°_sp）对pH调节过程中沉淀形成机制进行讨论。结果表明，pH=2.18~10时离子强度I在0.10mol/L左右，pH=12时离子强度I为0.59mol/L；考虑离子强度I影响时沉淀产物的活度积K°_sp与溶度积K_sp相比最大，可相差15个数量级，对于涂装废水沉淀产物生成预测时应采用活度积K°_sp进行判定；pH对弱酸弱碱各型体的存在浓度影响很大，pH=4~8时形成的沉淀产物主要为磷酸盐，pH=10~12时氢氧化物沉淀种类增加，pH=12时形成的沉淀产物种类最多。

关键词: 涂装废水, 热力学模型, 沉淀形成, 模拟预测

CLC Number:

X703

FU Haijuan, CHI Yongzhi, ZHAO Jianhai, CAO Lingyun, TIAN Binghui, FEI Xuening, FU Cuilian. Prediction and verification of precipitate formation in the coating wastewater under different pH[J]. Chemical Industry and Engineering Progress, 2018, 37(12): 4939-4947.

付海娟, 池勇志, 赵建海, 曹凌云, 田秉晖, 费学宁, 付翠莲. 不同pH下涂装废水中沉淀物形成的计算模拟预测及验证[J]. 化工进展, 2018, 37(12): 4939-4947.

References

[1] 刘绍根, 孙菁, 成雄剑, 等. SBR反应器中好氧颗粒污泥处理汽车涂装废[J]. 化工进展, 2012, 31(5):1160-1164, 1177. LIU S G, SUN J, CHENG X J, et al. Coating wastewater treatment by aerobic granular sludge in SBR[J]. Chemical Industry and Engineering Progress, 2012, 31(5):1160-1164, 1177.
[2] DEVI A, SINGHAL A, GUPTA R, et al. A study on treatment methods of spent pickling liquor generated by pickling process of steel[J]. Clean Technologies & Environmental Policy, 2014, 16(8):1515-1527.
[3] XIONG Z K, CAO J Y, YANG D, et al. Coagulation-flocculation as pre-treatment for micro-scale Fe/Cu/O₃ process (CF-mFe/Cu/O₃) treatment of the coating wastewater from automobile manufacturing[J]. Chemosphere, 2017, 166:343-351.
[4] 李明喜. 整车厂涂装车间废水处理工艺及应用研究[D]. 长春:吉林大学, 2013. LI M X. Wasterwater treatment of OEMs painting workshop and its application research[D]. Changchun:Jilin University, 2013.
[5] 徐淼, 冯海军, 刘晓亮, 等. 二级中和/固液分离膜技术处理酸洗废水与回用[J]. 中国给水排水, 2011, 27(16):88-92. XU M, FENG H J, LIU X L, et al. Two-stage neutralization/solid-liquid separation membrane for treatment and reuse of acid pickling wastewater from steel industry[J]. China Water & Wastewater, 2011, 27(16):88-92.
[6] 李文朴, 卢静芳, 柳美乐, 等. 高岭土对氢氧化镁混凝去除活性橙染料效果的影响[J]. 化工进展, 2017, 36(11):4286-4292. LI W P, LU J F, LIU M L, et al. Effect of Kaolin on the removal of reactive orange by magnesium hydroxide coagulation process[J]. Chemical Industry and Engineering Progress, 2017, 36(11):4286-4292.
[7] 李新颖, INNOCENT F R, 陈泉源. 含锌离子模拟废水沉淀研究及污泥表征[J]. 环境工程学报, 2013, 7(5):1859-1864. LI X Y, INNOCENT F R, CHEN Q Y. Precipitation of simulated wastewater containing zinc ions and characterization of sludge[J]. Chinese Journal of Environmental Engineering, 2013, 7(5):1859-1864.
[8] CHEN L, ZHOU C H, ZHANG H, et al. Capture and recycling of ammonium by dolomite-aided struvite precipitation and thermolysis[J]. Chemosphere, 2017, 187:302-310.
[9] LEE S H, KUMAR R, JEON B H. Struvite precipitation under changing ionic conditions in synthetic wastewater:experiment and modeling[J]. Journal of Colloid & Interface Science, 2016, 474:93-102.
[10] LEE S H, YOO B H, LIM S J, et al. Development and validation of an equilibrium model for struvite formation with calcium co-precipitation[J]. Journal of Crystal Growth, 2013, 372(3):129-137.
[11] GADEKAR S, PULLAMMANAPPALLIL P. Validation and applications of a chemical equilibrium model for struvite precipitation[J]. Environmental Modeling & Assessment, 2010, 15(3):201-209.
[12] 赵颖颖, 张焱, 邢贞干, 等. CO₂海水脱钙后主要体系中镁盐的结晶[J]. 化工进展, 2017, 36(7):2400-2406. ZHAO Y Y, ZHANG Y, XING Z G, et al. Research on the crystallization process of magnesium salt in major system of decalcified seawater[J]. Chemical Industry and Engineering Progress, 2017, 36(7):2400-2406.
[13] JOHANSSON B, FRIMAN R, HAKANPÄÄ-LAITINEN H, et al. Solubility and interaction parameters as references for solution properties Ⅱ:Precipitation and aggregation of asphaltene in organic solvents[J]. Advances in Colloid & Interface Science, 2009, 147/148(12):132-143.
[14] SHEN S B, TYAGI R D, BLAIS J F. Prediction of metal precipitates in tannery sludge leachate based on thermodynamic calculations[J]. Environmental Technology, 2001, 22(8):961-970.
[15] RONTELTAP M, MAURER M, GUJER W. The behaviour of pharmaceuticals and heavy metals during struvite precipitation in urine[J]. Water Research, 2007, 41(9):1859-1868.
[16] 国家环境保护总局《水和废水监测分析方法》编委会. 水和废水监测分析方法[M]. 4版. 北京:中国环境科学出版社, 2002. State Environmental Protection Administration.Monitoring and analysis method of water and wastewater[M]. 4th ed. Beijing:China Environmental Science Press, 2002.
[17] EJSMONT-KARABIN J. Ammonia nitrogen and inorganic phosphorus excretion by the planktonic rotifers[J]. Hydrobiologia, 1983, 104(1):231-236.
[18] STEPHENS K. Determination of low phosphate concentrations in lake and marine waters[J]. Limnology & Oceanography, 1963, 8(3):361-362.
[19] 胡明强. 基于难溶碳酸盐沉淀形成的海水封存二氧化碳研究[D]. 济南:山东大学, 2011. HU M Q. Study on CO₂ sequestration through carbonate precipitate formation in sea water[D]. Jinan:Shandong University, 2011.
[20] Li Y, Cundy A B, Feng J, et al. Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism[J]. Journal of Environmental Management, 2017, 192:100-106.
[21] LEAL A M M, KULIK D A, SAAR M O. Enabling Gibbs energy minimization algorithms to use equilibrium constants of reactions in multiphase equilibrium calculations[J]. Chemical Geology, 2016, 437:170-181.
[22] 黄君礼. 水分析化学[M]. 3版. 北京:中国建筑工业出版社, 2008. HUANG J L. Water analytical chemistry[M]. 3rd ed. Beijing:China Architecture & Building Press, 2008.
[23] TANGANOV B B, ALEKSEEVA I A. A method for calculating the acid-base equilibria in aqueous and nonaqueous electrolyte solutions[J]. Russian Journal of Physical Chemistry A, 2017, 91(6):1149-1151.
[24] ZHU M. Davies type estimate and the heat kernel bound under the Ricci flow[J]. Transactions of the American Mathematical Society, 2016, 368:30-38.
[25] STARIKOVA T A, LYSOVA S S, ZEVATSKⅡ Y E. Protolytic equilibrium constant and colligative properties of mono-and polyelectrolyte solutions[J]. Fibre Chemistry, 2015, 47(3):156-160.
[26] LYSOVA S S, STARIKOVA T A, ZEVATSKⅡ Y E. Limit of concentration constant of protolytic equilibrium[J]. Russian Journal of General Chemistry, 2014, 84(8):1634-1635.
[27] MORISHITA M, KINOSHITA Y, HOUSHIYAMA H, et al. Thermodynamic properties for calcium molybdate, molybdenum tri-oxide and aqueous molybdate ion[J]. Journal of Chemical Thermodynamics, 2017, 114:30-43.
[28] SHKOL'NIKOV E V. Thermodynamic characteristics of the amphoterism of M(OH)₂ hydroxides in aqueous media[J]. Russian Journal of Applied Chemistry, 2005, 78(11):1786-1790.
[29] PROVAZI K, GIZ M J, DALL'ANTONIA L H, et al. The effect of Cd, Co, and Zn as additives on nickel hydroxide opto-electrochemical behavior[J]. Journal of Power Sources, 2001, 102(1/2):224-232.
[30] SHI L, WANG F Q, JING W U, et al. Thermodynamics analysis of typical dyeing and printing wastewater heat pump heat recovery[J]. Journal of Thermal Science & Technology, 2014, 13(4):303-311.
[31] 蒋旭光, 张绍睿, 严建华. 室燃炉共处置危险废物研究现状及其发展思考[J]. 化工进展, 2016, 35(7):2195-2204. JIANG X G, ZHANG S R, YAN J H. Research status and opinion on the development of co-disposing hazardous waste in suspension firing boiler[J]. Chemical Industry and Engineering Progress, 2016, 35(7):2195-2204.