Efficient microalgae harvesting: Synergistic flocculation and flotation with polyacrylamide and graphite electrolysis

IF 6.7 2区环境科学与生态学 Q1 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Environmental Technology & Innovation Pub Date : 2025-05-22 DOI:10.1016/j.eti.2025.104281

Xuexia Zhu , Tianchi Yin , Lei Yin , Xuanhe Jia , Jun Wang

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引用次数: 0

Abstract

Microalgae offer widespread applications, yet their harvesting remains challenging due to the limitations of conventional methods like centrifugation, filtration, and chemical flocculation, which often involve high energy costs, complex equipment, or environmental risks. This study investigated the efficiency of combining polyacrylamide (PAM) flocculation with electro-flotation to harvest Chlorella vulgaris, a widely cultivated microalgal species for biofuel production. The results demonstrated that PAM-electro-flotation significantly improved harvesting rates while reducing costs, with a PAM concentration of 5–10 mg L^–1 and electrolysis at 30 A m^–2 for 60 to 120 seconds being the most effective and energy-saving combination. At 10 mg L^–1 PAM concentration, a 95 % harvesting rate only needed 7.24 × 10^–5 kWh L^–1, while nearly 100 % efficiency required around 4.97 × 10^–4 kWh L^–1. During electrolysis, phosphate concentrations decreased, and dissolved oxygen levels increased, supporting its potential for wastewater treatment. The method, utilizing nontoxic PAM and graphite electrodes, didn’t significantly affect microalgae photosynthetic efficiency (QY-24h > 0.65), especially at low PAM levels (≤5 mg L^–1) and current densities (≤20 A m^–2). Our study develops a PAM-electro-flotation system with optimal parameters, proving to be an efficient, environmentally friendly, cost-effective, and microalgae-safe method for microalgae harvesting.

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高效微藻收获：聚丙烯酰胺和石墨电解协同絮凝和浮选

微藻具有广泛的应用，但由于离心、过滤和化学絮凝等传统方法的局限性，它们的收获仍然具有挑战性，这些方法通常涉及高能源成本、复杂的设备或环境风险。本文研究了聚丙烯酰胺（PAM）絮凝与电浮选相结合对生物燃料微藻小球藻（Chlorella vulgaris）的回收效果。结果表明，PAM-电浮选显著提高了采收率，同时降低了成本，其中PAM浓度为5-10 mg L-1，电解温度为30 a m-2，电解时间为60 ~ 120 秒是最有效且节能的组合。在PAM浓度为10 mg L-1时，95% %的收获率仅需7.24 × 10 - 5 kWh L-1，而接近100% %的效率需要4.97 × 10 - 4 kWh L-1。在电解过程中，磷酸盐浓度降低，溶解氧水平增加，支持其在废水处理中的潜力。使用无毒PAM和石墨电极的方法对微藻光合效率没有显著影响(QY-24h >；0.65)，特别是在低PAM水平（≤5 mg L-1）和电流密度（≤20 A m-2）时。本研究开发了一种具有最佳参数的pam -电浮选系统，证明该系统是一种高效、环保、经济、安全的微藻收获方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Environmental Technology & Innovation Environmental Science-General Environmental Science

CiteScore

14.00

自引率

4.20%

发文量

435

审稿时长

74 days

期刊介绍： Environmental Technology & Innovation adopts a challenge-oriented approach to solutions by integrating natural sciences to promote a sustainable future. The journal aims to foster the creation and development of innovative products, technologies, and ideas that enhance the environment, with impacts across soil, air, water, and food in rural and urban areas. As a platform for disseminating scientific evidence for environmental protection and sustainable development, the journal emphasizes fundamental science, methodologies, tools, techniques, and policy considerations. It emphasizes the importance of science and technology in environmental benefits, including smarter, cleaner technologies for environmental protection, more efficient resource processing methods, and the evidence supporting their effectiveness.