硅酸盐学报

粉煤灰基陶粒的制备及其对水体中磷的吸附性能

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韩旭 ¹ , 许康 ² , 张天苇 ² , 李姬蓉 ¹ , 刘煜东 ¹ , 于佳滨 ¹ , 姜东 ¹ , 张亚平 ²

硅酸盐学报 | 研究论文 2026,54(4): 1407-1418

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硅酸盐学报 | 研究论文 2026, 54(4): 1407-1418

粉煤灰基陶粒的制备及其对水体中磷的吸附性能

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韩旭¹, 许康², 张天苇², 李姬蓉¹, 刘煜东¹, 于佳滨¹, 姜东¹, 张亚平²

作者信息

^1．华能南京金陵发电有限公司，南京 210034

^2．东南大学能源与环境学院，能源热转换及其过程测控教育部重点实验室，南京 210096

韩旭（1985—），男，工程师。

HAN Xu (1985-), male, Engineer. E-mail: 304409418@qq.com

通讯作者:

张亚平（1979—），女，博士，教授。

Preparation of Fly Ash Ceramsite and Its Phosphate Adsorption Performance

Xu HAN¹, Kang XU², Tianwei ZHANG², Jirong LI¹, Yudong LIU¹, Jiabin YU¹, Dong JIANG¹, Yaping ZHANG²

Affiliations

^1.Huaneng Nanjing jinling Electric Power Plant, Nanjing 210034, China

^2.Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, China

出版时间: 2026-03-11 doi: 10.14062/j.issn.0454-5648.20250746

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摘要

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本工作以粉煤灰为主原料，辅以市政污泥、炉渣和水泥制备陶粒，用于水体中磷的去除。通过单因素和正交实验优化制备条件，结合等温与动力学模型及SEM、XRD、XPS等手段，分析吸附性能与机理。结果表明，实验条件为原料（粉煤灰、市政污泥、炉渣、水泥）质量比7.0^∶3.0^∶2.0^∶1.2、600 ℃预热5 min、1050 ℃烧结5 min、升温速率5 ℃/min时，陶粒对磷吸附率达90.77%。Sips模型与拟一级动力学模型拟合效果最佳，表明吸附为表面非均匀过程。表征显示陶粒表面粗糙、比表面积大，主要晶体为莫来石和钙长石，Ca、Mg等组分与磷酸盐反应生成Ca₅（PO₄）₃（OH）、CaHPO₄·2H₂O和Mg₃（PO₄）₂，实现物理吸附与化学沉淀协同除磷。

关键词

粉煤灰 / 陶粒 / 工艺优化 / 磷 / 吸附机理

Abstract

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Introduction

Phosphorus (P) is an essential nutrient for aquatic ecosystems. However, excessive phosphorus discharge into surface water is one of the primary causes of eutrophication, thus triggering algal blooms, degrading water quality, and threatening aquatic life as well as human health. It is widely recognized that even low concentrations of phosphorus can significantly accelerate eutrophication processes, making efficient phosphorus removal a critical issue in water pollution control. Among the existing treatment technologies, adsorption has attracted increasing attention due to its operational simplicity, high efficiency for low-concentration phosphorus, and limited risk of secondary pollution.

Coal fly ash is one of the most abundant industrial solid wastes that are generated in large quantities in coal-fired power plants. Although its comprehensive utilization rate is increased, a considerable fraction of fly ash is still disposed of by landfilling or stockpiling, posing long-term environmental risks. Fly ash is a promising precursor for the preparation of ceramic materials due to its high contents of SiO₂ and Al₂O₃. Moreover, the presence of Ca, Mg, and other alkaline components endows fly-ash-derived materials with a potential chemical affinity toward phosphate species. Transforming fly ash into functional ceramsite for water treatment therefore represents a typical "waste-to-resource" strategy.

Previous studies explored fly-ash-based ceramsite or related materials for phosphorus removal. However, most of them focused primarily on adsorption performance evaluation, while systematic optimization of preparation parameters and in-depth clarification of phosphorus removal mechanisms remained insufficient. Such limitations hinder the rational design and engineering application of these materials. In this work, fly ash was used as a main raw material, supplemented with municipal sludge, furnace slag, and cement to prepare porous ceramsite for phosphorus removal. The adsorption behavior, comprehensive physicochemical characterization, preparation conditions, and removal mechanism were systematically investigated.

Methods

Fly-ash-based ceramsite was prepared by a disc granulation method. Fly ash was mixed with municipal sludge as a pore-forming component, furnace slag as a functional additive, and cement as a binder. After granulation with deionized water, green pellets with a controlled particle size were obtained and subjected to preheating and high-temperature sintering. To optimize the preparation process, a Taguchi L25 (5⁶) orthogonal experimental design was employed, considering six factors, i.e., fly ash-to-sludge ratio, preheating temperature, preheating time, sintering temperature, sintering time, and heating rate. Phosphate removal efficiency was selected as an evaluation index to determine the optimal preparation parameters.

Batch adsorption experiments were conducted using simulated phosphate solutions prepared from potassium dihydrogen phosphate. The effects of dosage, initial pH value, coexisting ions, and humic acid were systematically investigated to evaluate adsorption adaptability under different water chemistry conditions. Adsorption isotherms were analyzed using the Langmuir, the Freundlich, the Sips, and the Dubinin-Radushkevich models, while adsorption kinetics were interpreted using pseudo-first-order, pseudo-second-order models, i.e., Elovich, and intraparticle diffusion models.

The physicochemical properties and adsorption mechanisms of the ceramsite were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the leaching risk of heavy metals was also assessed using standard toxicity characteristic leaching procedures to evaluate environmental safety.

Results and Discussion

The results of orthogonal experimental analysis reveal that sintering temperature is the most dominant factor affecting phosphate removal performance, following by sintering time and heating rate. The excessively high sintering temperature leads to pore collapse and crystallization of stable mineral phases, thereby reducing adsorption capacity. The optimal preparation conditions obtained are a fly ash-to-municipal sludge ratio of 7∶3, preheating at 600 ℃ for 5 min, sintering at 1050 ℃ for 5 min, and a heating rate of 5 ℃/min. Under the optimal conditions, the ceramsite achieves a phosphate removal efficiency of 90.77%, which is significantly higher than that of all orthogonal experimental groups.

The SEM images show that the optimized ceramsite has a rough surface with abundant interconnected pores, originating from the thermal decomposition of organic matter in municipal sludge and gas evolution during high-temperature reactions. The XRD patterns indicate that mullite and anorthite are the dominant crystalline phases, while Ca- and Mg-containing components are retained in reactive forms. The results of batch experiments demonstrate that phosphate removal efficiency increases with increasing dosage but decreases under strong alkaline conditions. The ceramsite maintains effective phosphorus removal in a wide range of pH values, with optimal performance under weakly acidic to neutral conditions.

The coexisting anions exhibit varying degrees of inhibition on phosphate removal, following a decreasing order CO₃^2- >HCO₃^- > SO₄^2- > NO₃^- > Cl^-, whereas common monovalent cations show a negligible influence. In contrast, the presence of Ca²⁺ and Mg²⁺ significantly enhances phosphate removal due to additional precipitation reactions. Humic acid notably suppresses adsorption via competing for active sites and altering phosphate speciation.

Adsorption isotherm analysis shows that the Langmuir and Sips models both fit the experimental data, while the Sips model provides a better physical interpretation, indicating a heterogeneous surface adsorption. The kinetic analysis reveals that the pseudo-first-order model can describe the adsorption process, indicating that surface reactions are dominant the rate-controlling step. The XPS spectra confirm the formation of Ca- and Mg-phosphate species on the ceramsite surface after adsorption, showing that phosphate removal occurs based on a synergistic mechanism involving physical adsorption and chemical precipitation.

The results of leaching tests indicate that the concentrations of heavy metals released from the ceramsite are well below regulatory limits, having its environmental safety for water treatment applications.

Conclusions

A fly-ash-based ceramsite was prepared using municipal sludge and furnace slag as auxiliary components for efficient phosphate removal in water. The ceramsite exhibited a high removal efficiency, a broad pH value adaptability, and a stable performance under complex water chemistry conditions via systematic optimization of preparation parameters and comprehensive adsorption studies. The phosphate removal mechanism was dominated due to the synergistic effect of surface adsorption and Ca/Mg-induced chemical precipitation. Moreover, the ceramsite showed a negligible heavy-metal leaching risk, indicating a good environmental compatibility. This study could provide a feasible approach for the large-scale resource utilization of fly ash and offer a promising adsorbent for phosphorus control in aquatic environments.

Key words

fly ash / ceramsite / process optimization / phosphorus / adsorption mechanism

引用本文

韩旭, 许康, 张天苇, 李姬蓉, 刘煜东, 于佳滨, 姜东, 张亚平. 粉煤灰基陶粒的制备及其对水体中磷的吸附性能. 硅酸盐学报, 2026 , 54 (4) : 1407 -1418 . DOI: 10.14062/j.issn.0454-5648.20250746

Xu HAN, Kang XU, Tianwei ZHANG, Jirong LI, Yudong LIU, Jiabin YU, Dong JIANG, Yaping ZHANG. Preparation of Fly Ash Ceramsite and Its Phosphate Adsorption Performance[J]. Journal of the Chinese Ceramic Society, 2026 , 54 (4) : 1407 -1418 . DOI: 10.14062/j.issn.0454-5648.20250746

基金

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国家重点研发计划(2020YFC1908703)

参考文献

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2026年第54卷第4期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250746

接收时间：2025-10-10
首发时间：2026-05-20
出版时间：2026-03-11

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收稿日期：2025-10-10
修回日期：2025-12-29

基金

国家重点研发计划(2020YFC1908703)

作者信息

^1．华能南京金陵发电有限公司，南京 210034

^2．东南大学能源与环境学院，能源热转换及其过程测控教育部重点实验室，南京 210096

通讯作者:

张亚平（1979—），女，博士，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250746

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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