Preparation of g-C3N4/Bismuth Iodide/Tourmaline Composites and Their Photodegradation Performance of Amaranthine

Abstract

In this study, g-C3N4/BiOI/tourmaline composites were synthesized by loading BiOI and tourmaline on g-C3N4 nanofilms using g-C3N4, BiOI, and tourmaline as raw materials, aiming to optimize the photocatalytic degradation of amaranth red dye wastewater (AR). Single-factor experiments were conducted to optimize the degradation process. The findings indicate that a degradation rate of 95.88% can be achieved for AR within 150 min of light exposure, given a g-C3N4/BiOI/tourmaline dosage of 1 g/L, an initial pH level of 3 for the AR, and an initial AR concentration of 10 mg/L. Upon repeating the experiment for five cycles, the composite exhibited 83.10% activity, demonstrating its stability. Various analytical techniques were employed for material characterization: X-ray diffractometry (XRD) to ascertain the crystalline structure, field-emission scanning electron microscopy (FESEM) to evaluate morphology, X-ray photoelectron spectroscopy (XPS) for elemental analysis, ultraviolet–visible diffuse reflectance spectroscopy (UV-vis DRS) for optical properties, and photoluminescence (PL) spectroscopy to analyze the recombination of excited electrons and holes. Free radical masking experiments further elucidated the photocatalytic mechanism, revealing that the primary active species in the degradation process is the superoxide anion (O2−). This research offers a novel approach to address the limitations of n-type metal-free semiconductor photocatalysts.