A technology of foam fractionation coupled with crystallization was developed for effectively recovering materials from wastewaters with low concentrations. The wastewater containing folic acid (FA) was used as a system and cetyltrimethyl ammonium bromide (CTAB) was chosen as a collector to recover FA from its wastewater. The results showed that the technology could effectively enrich and purify FA with a low concentration of 6 mg/L from its wastewater. In foam fractionation, the enrichment ratio and recovery percentage of FA were 86.1% and 69.1%, respectively. CTAB could be reused using a two-stage foam fractionation. In crystallization, the recovered FA had 98.0% in purity and it met the quality standard (GB 15570-95). The total recovery percentage of FA was 66.0% by the technology of foam fractionation coupled with crystallization. The technology could be effective not only for recovering FA from its wastewater but also for recovering other trace materials from their wastewaters. (C) 2014 Elsevier B.V. All rights reserved.