光伏行业废水中高浓度氟离子核晶造粒回收效能与机制研究

In response to the challenge of coexisting high concentrations of fluoride (F^-) and sulfate (SO₄^2-) in photovoltaic wastewater, based on the principle of nucleation crystallization pelleting process (NCP), its efficacy and mechanisms for removing Fin such ion coexistence systems were thoroughly investigated. Our study demonstrated that under conditions (nucleation inducer dosage 4.46gMgCl₂/gF, flow rate 67.8×10^-4m³/h, static bed height 30%, and seed particle size 80~100mesh, F^- removal efficiency reached up to 90%. To further validate the stability of the process system, continuous flow defluorination experiments were conducted over 120h. In the first stage (0~40hours), F^- removal efficiency stabilized at approximately 89%, increasing to over 92% in the second stage (40~120hours), with granule purity exceeding 90%. Analysis using XRD and Roman revealed that F^- predominantly adhered to seed surfaces in the forms of magnesium fluoride (MgF₂) and sodium magnesium fluoride (NaMgF₃). Static water contact angle tests and SEM-EDS characterization indicated that granules exhibited greater hydrophobicity compared to the raw seeds and formed a loose porous structure, thereby increasing their specific surface area and enhancing F^- removal. The ZP revealed that in pH 6~8, the seed surface was positively charged, and F^- was mainly concentrated around the surface of the seeds by electrostatic attraction, and then driven by the inducer to nucleate and grow into dense granulation on the surface of the seeds, effectively separating F^- from water.