Delsa 440sx

A Coulter Delsa 440sx zeta analyzer (Beckman Coulter, Brea, CA, USA) was used to perform zeta potential measurement. A KCl solution (1 × 10⁻³ mol/L) was used as a supporting electrolyte. A total of 30 mg of the −2 μm sample was used for each test. The pulp preparation process for the test was identical to that of the microflotation investigation. Zeta potential was measured using the supernatant liquor after the pulp settled for 10 min. At each reagent condition, at least three independent tests were performed.

The DMSA-coated magnetite FeNPs were synthesized by thermal decomposition [69 (link)]. The size and dispersibility of the FeNPs were evaluated using a transmission electron microscope (JEM-2100). The hydrodynamic size distribution of the FeNPs was analyzed with a submicron particle analyzer (Beckman Coulter N4 Plus). The surface charge of the FeNPs was measured with a zeta potential analyzer (Beckman Coulter Delsa 440SX).

The Diffuse Reflectance Infrared Fourier Transform Spectroscopy were tested by a Shimadzu FTIR 8120 spectrometer at a wavenumber range between 4000 and 600 cm⁻¹. The SEM images were examined by a Mira3 LMU SEM (Tescan, Czech Republic) with the voltage of 20 kV. The TEM images and EDX mapping analysis were collected with a Titan G2 60-300 with the voltage of 30 kV. The differential thermal analysis was analyzed using the STA449C (NETZSCH, GER), which ranged from 30 to 1000 °C with 5 °C/min rate of rise. XRD measurements were obtained by Rigaku TTR III at range between 5 and 80°. The absorbance (OD) value was obtained from a microplate reader (EnVision Xcite, PerkinElmer). Zeta potentials of samples were measured with a Zeta-sizer Delsa440sx instrument (Beckman Coulter, Brea, CA, USA). The water contact angle was tested with a contact angle goniometer (JY-82C, Chengde Dingsheng Testing Machine Testing Equipment Co., Ltd.). OriginPro (version 8.5) was used to treated the data for materials properties analysis.