Effect of thermal treatment coupled with acid activation on phosphate adsorption by alum sludge
CHEN Ai-xia1,2,3, PU Ma-xue-er1,2,3, LYU Lu-xue4, WEI Xiao1,2,3, GAO Ya-jun1,2,3, FAN Zhi-jie1,2,3
1. School of Water and Environment, Chang'an University, Xi'an 710054, China; 2. Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of the Ministry of Education, Chang'an University, Xi'an 710054, China; 3. Key Laboratory of Eco-hydrology and Water Security in Arid and Semi-arid Regions of Ministry of Water Resources, Chang'an University, Xi'an 710054, China; 4. Karamay Ecological Environment Bureau, Karamay 834000, China
Abstract：Alum sludge (AIS) originating from water treatment plants possesses notable phosphate adsorption and chelating capabilities, due to its rich content of aluminum and iron oxides. However, the effectiveness of AIS in phosphate adsorption is often hampered by its complex composition and the presence of impurities. To overcome these obstacles, this study adopted a simple yet effective method that combines thermal treatment with acid activation. The results showed that after being subjected to thermal treatment at 600℃ for 1hour and then activated with 2.0mol/L hydrochloric acid at a solid-liquid ratio of 1:1, the AIS achieved a phosphate adsorption capacity of 18.3mg/g. This represented a 2.4-fold increase compared to the untreated AIS. Furthermore, the treated AIS demonstrated remarkable stability in tests involving the coexistence of anions and cations, as well as metal ion dissolution. The investigation into adsorption kinetics and thermodynamics revealed that the adsorption process was primarily driven by chemisorption. Complementary analyses using SEM, XRD, and BET further confirmed that the adsorption mechanism was dominated by ligand exchange. Additionally, electrostatic attraction, hydrogen bonding, and surface deposition also played pivotal roles in the adsorption process. These findings not only provide a promising perspective on alum sludge disposal and phosphorus pollution control but also embody a promising win-win strategy of "turning waste into treasure"
[1] Chittoo B S, Sutherland C. Adsorption using lime-iron sludge- encapsulated calcium alginate beads for phosphate recovery with ANN- and RSM-Optimized encapsulation [J]. Journal of Environmental Engineering, 2019,145(5):04019019. [2] Ho J C, Michalak A M, Pahlevan N. Widespread global increase in intense lake phytoplankton blooms since the 1980s [J]. Nature, 2019, 574(7780):667-670. [3] Xu W S, Zheng W J, Wang F J, et al. Using iron ion-loaded aminated polyacrylonitrile fiber to efficiently remove wastewater phosphate [J]. Chemical Engineering Journal, 2021,403:126349. [4] Yang Y, Koh K Y, Li R, et al. An innovative lanthanum carbonate grafted microfibrous composite for phosphate adsorption in wastewater [J]. Journal of Hazardous Materials, 2020,392:121952. [5] 王倩,杜晓丽,崔申申,等.给水厂污泥颗粒制备及对铜离子的吸附行为[J]. 中国环境科学, 2019,39(4):1672-1677. Wang Q, Du X L, Cui S S, et al. Preparation of granular sludge from water supply plants and its adsorption behavior of copper ions [J]. China Environmental Science, 2019,39(4):1672-1677. [6] 王建军,李田,张颖.给水厂污泥改良生物滞留填料除磷效果的研究[J]. 环境科学, 2014,35(12):4642-4647. Wang J J, Li T, Zhang Y. Water treatment residual as a bioretention media amendment for phosphorus removal [J]. Environmental Science, 2014,35(12):4642-4647. [7] Bai L L, Wang C H, He L S, et al. Influence of the inherent properties of drinking water treatment residuals on their phosphorus adsorption capacities [J]. Journal of Environmental Sciences, 2014,26(12):2397- 2405. [8] Zhao Y Q, Babatunde A O, Hu Y S, et al. Pilot field-scale demonstration of a novel alum sludge-based constructed wetland system for enhanced wastewater treatment [J]. Process Biochemistry, 2011,46(1):278-283. [9] 刘珊,张悦,田薪成,等.海藻酸钠改性铝污泥功能球吸附Cu(Ⅱ)的研究[J]. 应用化工, 2020,49(1):11-16. Liu S, Zhang Y, Tian X C, et al. Adsorption copper ions from aqueous solution onto sodium alginate chemically modified aluminum sludge [J]. Applied Chemical Industry, 2020,49(1):11-16. [10] Shen C, Zhao Y Q, Li W X, et al. Global profile of heavy metals and semimetals adsorption using drinking water treatment residual [J]. Chemical Engineering Journal, 2019,372:1019-1027. [11] Muisa N, Nhapi I, Ruziwa W, et al. Utilization of alum sludge as adsorbent for phosphorus removal in municipal wastewater: A review [J]. Journal of Water Process Engineering, 2020,35:101187. [12] Jo J Y, Kim J G, Tsang Y F, et al. Removal of ammonium, phosphate, and sulfonamide antibiotics using alum sludge and low-grade charcoal pellets [J]. Chemosphere, 2021,281:130960. [13] Omoike A I, Vanloon G W. Removal of phosphorus and organic matter removal by alum during wastewater treatment [J]. Water Research, 1999,33(17):3617-3627. [14] Liu R B, Zhao Y Q, Sibille C, et al. Evaluation of natural organic matter release from alum sludge reuse in wastewater treatment and its role in P adsorption [J]. Chemical Engineering Journal, 2016,302:120- 127. [15] Aghapour A A, Khorsandi H, Dehghani A, et al. Preparation and characterization and application of activated alumina (AA) from alum sludge for the adsorption of fluoride from aqueous solutions: New approach to alum sludge recycling [J]. Water Supply, 2018,18(5): 1825-1831. [16] Van T T, Kim D J. Synthesis of high quality boehmite and γ-alumina for phosphorus removal from water works sludge by extraction and hydrothermal treatment [J]. Environmental Research, 2022,212: 113448. [17] 张佳钰.海藻酸钠包埋污泥凝胶球的制备及除氟机理研究[D]. 沈阳:沈阳建筑大学, 2023. Zhang J Y. Study on the preparation and mechanism of sodium alginate entrapped sludge gel beads for fluoride removal [D]. Shenyang: Shenyang Jianzhu University, 2023. [18] Everaert M, Bergmans J, Broos K, et al. Granulation and calcination of alum sludge for the development of a phosphorus adsorbent: From lab scale to pilot scale [J]. Journal of Environmental Management, 2021, 279:111525. [19] Matilainen A, Vepsäläinen M, Sillanpää M. Natural organic matter removal by coagulation during drinking water treatment: A review [J]. Advances in Colloid and Interface Science, 2010,159(2):189-197. [20] 吴慧芳,胡文华.聚合氯化铝污泥吸附除磷的改性研究[J]. 中国环境科学, 2011,31(8):1289-1294. Wu H F, Hu W H. Adsorption removal of phosphorus from aqueous solution using modified polyaluminium chloride sludge [J]. China Environmental Science, 2011,31(8):1289-1294. [21] Cardoso C M M, Zavarize D G, Lago P D A, et al. Evaluating adsorbent properties of drinking water treatment plant sludge-based carbons activated by K2CO3/CH3COOH: A low-cost material for metal ion remediation [J]. SN Applied Sciences, 2019,1(7):1-10. [22] Wang B, Zhang H, Hu X L, et al. Efficient phosphate elimination from aqueous media by La/Fe bimetallic modified bentonite: Adsorption behavior and inner mechanism [J]. Chemosphere, 2023,312(Pt 1): 137149. [23] Lian J J, Zhou F J, Chen B, et al. Enhanced adsorption of molybdenum(VI) onto drinking water treatment residues modified by thermal treatment and acid activation [J]. Journal of Cleaner Production, 2020,244:118719. [24] Jeon E K, Ryu S, Park S W, et al. Enhanced adsorption of arsenic onto alum sludge modified by calcination [J]. Journal of Cleaner Production, 2018,176:54-62. [25] Wang C H, Gao S J, Wang T X, et al. Effectiveness of sequential thermal and acid activation on phosphorus removal by ferric and alum water treatment residuals [J]. Chemical Engineering Journal, 2011, 172(2/3):885-891. [26] Chen A X, Lv L X, Hu R R, et al. Achieving win-win outcomes with cerium-loaded porous aluminum sludge hydrogel microspheres for enhanced phosphate removal [J]. Science of the Total Environment, 2023,867:161530. [27] Kloprogge J T, Ruan H D, Frost R L. Thermal decomposition of bauxite minerals: infrared emission spectroscopy of gibbsite, boehmite and diaspore [J]. Journal of Materials Science, 2002,37(6):1121-1129. [28] Al-Ghouti M A, Da'ana D A. Guidelines for the use and interpretation of adsorption isotherm models: A review [J]. Journal of Hazardous Materials, 2020,393:122383. [29] Chen S, Qin C X, Wang T, et al. Study on the adsorption of dyestuffs with different properties by sludge-rice husk biochar: Adsorption capacity, isotherm, kinetic, thermodynamics and mechanism [J]. Journal of Molecular Liquids, 2019,285:62-74. [30] Chen Y B, Tang J L, Wang S X, et al. Bimetallic coordination polymer for highly selective removal of Pb(II): Activation energy, isosteric heat of adsorption and adsorption mechanism [J]. Chemical Engineering Journal, 2021,425:131474. [31] Bhunia A, Bansal K, Henini M, et al. Negative activation energy and dielectric signatures of excitons and excitonic mott transitions in quantum confined laser structures [J]. Journal of Applied Physics, 2016,120(14):144304. [32] Yang Y, Wang Y N, Zheng C Y, et al. Lanthanum carbonate grafted ZSM-5for superior phosphate uptake: Investigation of the growth and adsorption mechanism [J]. Chemical Engineering Journal, 2022,430: 133166. [33] Guo Y, Xing X, Shang Y N, et al. Multiple bimetallic (Al-La or Fe-La) hydroxides embedded in cellulose/graphene hybrids for uptake of fluoride with phosphate surroundings [J]. Journal of Hazardous Materials, 2019,379:120634. [34] Wang B, Zhang H, Xu Z Z, et al. La/Al engineered bentonite composite for efficient phosphate separation from aqueous media: Preparation optimization, adsorptive behavior and mechanism insight [J]. Separation and Purification Technology, 2022,290:120894. [35] Zhang W, Deng Q, He Q L, et al. A facile synthesis of core- shell/bead-like poly (vinyl alcohol)/alginate@PAM with good adsorption capacity, high adaptability and stability towards Cu(Ⅱ) removal [J]. Chemical Engineering Journal, 2018,351:462-472. [36] 欧阳铸,曹露,王炳乾,等.富含钙/铝的污泥生物炭复合材料对水溶液中磷酸盐的吸附机制[J]. 环境科学, 2023,44(5):2661-2670. Ouyang Z, Cao L, Wang B Q, et al. Adsorption mechanism for phosphate in aqueous solutions of calcium/aluminum-rich sludge biochar composite [J]. Environmental Science, 2023,44(5):2661-2670. [37] Shi L, Zhao X H, Cao Y X, et al. Physicochemical properties and phosphorus adsorption capacity of ceramsite made from alum sludge [J]. Water, 2023,15(13):2427. [38] Chen A X, Guan J J, Hu R R, et al. Enhanced phosphate adsorption studies on several metal-modified aluminum sludge: Preparation optimization, adsorption behavior, and mechanistic insight [J]. Environmental Science and Pollution Research, 2023,30(19):54628- 54643. [39] 曹露.废弃生物质制备生物炭及其磷酸盐吸附性能的研究[D]. 东莞:东莞理工学院, 2023. Cao L. Preparation of biochar from waste biomass and its adsorption properties for phosphate [D]. Dongguan: Dongguan University of Technology, 2023. [40] Lu J, Liu H, Zhao X, et al. Phosphate removal from water using freshly formed Fe-Mn binary oxide: Adsorption behaviors and mechanisms [J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014,455:11-18. [41] Li R H, Jim J, Zhou B Y, et al. Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios [J]. Science of the Total Environment, 2016,559:121- 129. [42] Nie G Z, Wu L R, Qiu S J, et al. Preferable phosphate sequestration using polymer-supported Mg/Al layered double hydroxide nanosheets [J]. Journal of Colloid and Interface Science, 2022,614:583-592. [43] 赵晓红,杨雨萌,王文科,等.壳聚糖改性铝污泥对铜绿微囊藻的絮凝去除[J]. 中国环境科学, 2021,41(10):4677-4685. Zhao X H, Yang Y M, Wang W K, et al. Chitosan modified alum sludge for alga M. aeruginosa removal by flocculation [J]. China Environmental Science, 2021,41(10):4677-4685. [44] Yu C L, Xian G J, Zhong L G, et al. Adsorption characteristics and removal mechanism of malathion in water by high and low temperature calcium-modified water hyacinth-based biochar [J]. Journal of Cleaner Production, 2023,411:137258. [45] Wang L, Wang A Q. Adsorption properties of congo red from aqueous solution onto N,O-carboxymethyl-chitosan [J]. Bioresource Technology, 2008,99(5):1403-1408. [46] Li R H, Wang J J, Zhou B Y, et al. Recovery of phosphate from aqueous solution by magnesium oxide decorated magnetic biochar and its potential as phosphate-based fertilizer substitute [J]. Bioresource Technology, 2016,215:209-214. [47] Kong L, Tian Y, Pang Z, et al. Synchronous phosphate and fluoride removal from water by 3D rice-like lanthanum-doped La@MgAl nanocomposites [J]. Chemical Engineering Journal, 2019,371:893- 902. [48] Shi W M, Fu Y W, Jiang W, et al. Enhanced phosphate removal by zeolite loaded with Mg-Al-La ternary (hydr)oxides from aqueous solutions: Performance and mechanism [J]. Chemical Engineering Journal, 2019,357:33-44. [49] Wang B, Zhang H, Xie Y J, et al. Synchronous gelation and lanthanum introduction using bentonite/PVA/SA as the matrix for efficient phosphate removal from aqueous media: Adsorptive behavior and mechanism study [J]. Journal of Cleaner Production, 2022,339: 130763. [50] Dong S X, Wang Y L, Zhao Y W, et al. La3+/La(OH)3loaded magnetic cationic hydrogel composites for phosphate removal: Effect of lanthanum species and mechanistic study [J]. Water Research, 2017, 126:433-441.
