Microwave-assisted decolorization and decomposition of methylene blue with persulfate

• Published in: International biodeterioration & biodegradation 2014-11, Vol.95, p.208-211
• Main Authors: KIm, Yong-Beom, Ahn, Johng-Hwa
• Format: Article
• Language: English
• Subjects: Boundaries; Conversion; Decoloring; Decomposition; Heating; Methylene blue; Microwave; Microwaves; Persulfate; Spark plasma sintering; Sulfate radical; Total organic carbon
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2014.03.023

This work experimentally determined the effect of a combination of microwave irradiation (MWI) and sodium persulfate (Na2S2O8, SPS) on decolorization and decomposition of methylene blue (C16H18N3SCl, MB). The effects of treatment temperature (70–100 °C, T) and SPS concentration (1–5 g l−1) at 8-min MWI time were characterized. The conversion rate of MB (50 mg l−1) was increased and accelerated by MWI, reaching 99.9% after heating for 8 min at 90 °C and 600-W MW power in the presence of 5 g l−1 of SPS; this is higher than the conversion rate (98.3%) of treatment by conventional heating for 30 min. The MB decolorization increased with T (p = 0.002) and initial SPS (p = 0.006). The total organic carbon (TOC) removal also increased with T (p = 0.004). Within the design boundaries, full decolorization was achieved at T ≥ 93 °C and SPS ≥3.5 g l−1. The TOC removal level reached 100% at T ≥ 95 °C and SPS = 5 g l−1. The results show that MWI combined with SPS is effective in decolorization and degradation of MB due to advantages of fast and effective processing. •Microwave with persulfate is an effective technique to degrade methylene blue (MB).•The MB removal rate increases with final temperature (T) and [perfulfate].•The T affects both decolorization and total organic carbon (TOC) removal of MB.•The [perfulfate] affects only decolorization of MB significantly.•The removal of TOC reaches 100% at higher T and [perfulfate] than decolorization.