UV–Vis spectrophotometry (Thermo Scientific, Waltham, MA, USA), pH meter (Eutech, Breda, The Netherlands), oven (Memmert, Schwabach, Germany) micropipette (DLAB, Beijing, China), beaker (Iwaki, Japan), Erlenmeyer (Iwaki, Japan), test tube (Iwaki, Japan), volumetric flask (Iwaki, Japan), stir bar, vacuum filter, volume pipette (Pyrex, Shizuoka, Japan), analytical balance (Sartorius, Göttingen, Germany), ultrasonic stirrer (Branson, MO, USA), Whatman No. 1, Whatman No. 41, Whatman No. 91, Whatman grade 1 chromatography paper, 0.45 µm membrane, and ImageJ software (National Institutes of Health, Bethesda, MD, USA).
AuNPs (10 nm diameter, OD 1) (Sigma Aldrich, St. Louis, MO, USA), cyanuric acid (Sigma Aldrich), ethanol (Merck, Darmstadt, Germany), double distilled H2O (Ikapharmindo Putramas, East Jakarta, Indonesia), HgCl2 (Smartlab, Semarang, Indonesia), MgSO4, ZnCl2, AgNO3, FeSO4, CdSO4, BaCl2, and MnCl2 (Merck, Germany), NaCl (Merck, Germany), Tris-HCl (Himedia, Kennett Square, PA, USA), as well as water samples from Kenanga Lake, FMIPA Lake, and Mahoni Lake.
AuNPs (10 nm diameter, OD 1) (Sigma Aldrich, St. Louis, MO, USA), cyanuric acid (Sigma Aldrich), ethanol (Merck, Darmstadt, Germany), double distilled H2O (Ikapharmindo Putramas, East Jakarta, Indonesia), HgCl2 (Smartlab, Semarang, Indonesia), MgSO4, ZnCl2, AgNO3, FeSO4, CdSO4, BaCl2, and MnCl2 (Merck, Germany), NaCl (Merck, Germany), Tris-HCl (Himedia, Kennett Square, PA, USA), as well as water samples from Kenanga Lake, FMIPA Lake, and Mahoni Lake.