Coffee husks were transformed into magnetic adsorption materials by the hydrothermal carbonization (HTC) method at low temperature (180 oC) in the presence of iron (III) salt. For the capability of absorbing methylene blue, the absorbed content by biochar is mg/g and by magnetic adsorption material is mg/g | Journal of Science and Technology 55 (4) (2017) 516-523 DOI: SYNTHESIS OF NOVEL MAGNETIC ADSORBENTS FROM COFFEE HUSKS BY HYDROTHERMAL CARBONIZATION Tran Thi Hien1, *, Nguyen The Vu2, Pham Huu Thien3, Nguyen Dinh Thanh3, Phan Dinh Tuan4 1 2 3 Industrial University of Hochiminh City, 12 Nguyen Van Bao Str., Go Vap Dist., Hochiminh City Hochiminh City Vocational College of Technology, 502 Do Xuan Hop Str., Dist. 9, Hochiminh City Institute of Applied Materials Science-VAST, 1 Mac Dinh Chi Str., Dist. 1, Hochiminh City 4 Hochiminh City University of Natural Resources and Environment, 236B Le Van Sy Street, Tan Binh Dist., Hochiminh City * Email: tranhien86@ Received: 15 December 2016; Accepted for publication: 3 August 2017 ABSTRACT Coffee husks were transformed into magnetic adsorption materials by the hydrothermal carbonization (HTC) method at low temperature (180 oC) in the presence of iron (III) salt. For the capability of absorbing methylene blue, the absorbed content by biochar is mg/g and by magnetic adsorption material is mg/g. Absorption capacity is also described through the isotherm Langmuir model. HTC is demonstrated as an alternative and effective approach in converting waste biomass into materials for waste water treatment. Keywords: hydrothermal carbonization, magnetic adsorption materials, coffee husks, agricultural waste. 1. INTRODUCTION Magnetic adsorption is a commonly used method to remove contaminants in water, with its high efficiency and wide adaptability [1, 2]. Most of the adsorbents were recovered by filtration or centrifugation. In recent years, the magnetic adsorbents are of a new research subject in water treatment to attain the adsorbent recovery. Magnetic adsorbents can easily be separated by using an external magnetic field [3, 4]. Currently, the utilization of biomass to make the application of adsorbent in removing contaminants, especially dyes from waste water is a very .
