Strong enhancement of methylene blue removal from binary wastewater by in-situ ferrite process

Haotian Hao , Yili Wang , Baoyou Shi , Kun Han , Yuan Zhuang , Yan Kong , Xin Huang


Received October 27, 2017,Revised , Accepted January 19, 2018, Available online February 03, 2018

Volume 30,2018,Pages 107-116

Dye wastewater containing heavy metal ions is a common industrial effluent with complex physicochemical properties. The treatment of metal–dye binary wastewater is difficult. In this work, a novel in-situ ferrite process (IFP) was applied to treat Methylene Blue (MB)–Cu(II) binary wastewater, and the operational parameters were optimized for MB removal. Results showed that the optimum operating conditions were OH/M of 1.72, Cu2 +/Fe2 + ratio of 1/2.5, reaction time of 90 min, aeration intensity of 320 mL/min, and reaction temperature of 40°C. Moreover, the presence of Ca2 + and Mg2 + moderately influenced the MB removal. Physical characterization results indicated that the precipitates yielded in IFP presented high surface area (232.50 m2/g) and a multi-porous structure. Based on the Langmuir model, the maximum adsorption capacity toward MB was 347.82 mg/g for the precipitates produced in IFP, which outperformed most other adsorbents. Furthermore, IFP rapidly sequestered MB with removal efficiency 5 to 10 times greater than that by general ferrite adsorption, which suggested a strong enhancement of MB removal by IFP. The MB removal process by IFP showed two different high removal stages, each with a corresponding removal mechanism. In the first brief stage (< 5 min), the initial high MB removal (~ 95%) was achieved by predominantly electrostatic interactions. Then the sweep effect and encapsulation were dominant in the second longer stage.

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