STUDY ON PREPARATION OF BIOCHIP BASED ON HIGH DENSITY POLYETHYLENE (HDPE) AND AZODICARBONAMIDE FOAMING AGENT

Vu Tien Giap; Nguyen Thuy Chinh; Nguyen Huu Dat; Nguyen Thi Dieu Linh; Tran Huu Trung; Bui Quoc Huy; Nguyen Thi Thuy Anh; Nguyen Vu Giang; Mai Duc Huynh

Vu Tien Giap Hung Yen Department of Science and Technology
Nguyen Thuy Chinh Vietnam Academy of Science and Technology
Nguyen Huu Dat Vietnam Academy of Science and Technology
Nguyen Thi Dieu Linh Vietnam Academy of Science and Technology
Tran Huu Trung Vietnam Academy of Science and Technology
Bui Quoc Huy Hung Yen University of Technology and Education
Nguyen Thi Thuy Anh Hung Yen University of Technology and Education
Nguyen Vu Giang Vietnam Academy of Science and Technology
Mai Duc Huynh Vietnam Academy of Science and Technology

Keywords: Moving bed biofilm reactor, porosity, biochip, high density polyethylene

Abstract

Domestic wastewater treatment by Moving Bed Biofilm Reactor (MBBR) technology has received great attention thanks to its many advantages including high organic treatment load, space saving, ease of operation and expansion of the process. However, the porous bio-carriers used in MBBR technology are mainly designed in the form of cylinders, spheres or cubes while the bio-carriers in the form of flat discs (biochip) having a large active surface area has been limited in study. Therefore, in this study, the porous biochips based high density polyethylene (PE) and different contents of azodicarbonamide (AC) as a foaming agent were fabricated using a PolyHaake single-screw extruder. Melting rheological analysis revealed that the most suitable extrusion time for preparation of PE biochips was 100 seconds to ensure complete expansion of AC. Infrared spectroscopy showed residual AC in the biochips when using it with the content higher than 2 wt.%. Scanning electron microscopy images show that the sample containing 2 wt.% of AC has uniform structure with the size of pores in range of 650 - 900 μm. Consequently, when using AC at higher contents, the density of pores and the distance between the pores in the samples increased. As increasing the AC content, the mechanical properties and density of biochips gradually decreased while their porosity increased. The porosity and density of the biochip containing 2 wt.% of AC were 30.21 % and 0.656 g/cm3, respectively. From obtained results, it can be used AC2 biochip as a bio-carrier in domestic wastewater treatment by MBBR technology.

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