Simultaneous removal of tartrazine and erythrosine B using MnFe-layered double hydroxide nanoparticles modified PVDF polymer membrane

Abstract

Tartrazine (TZ) and erythrosine B (EB) dyes are extensively utilized as colorants in numerous commercial applications, including pharmaceuticals, textiles, and consumer products. However, their widespread use leads to the discharge of dye-containing wastewater, posing significant risks to aquatic ecosystems and human health. In this study, the simultaneous removal of these dyes was systematically investigated using MnFe-layered double hydroxides (LDHs)/PVDF as a composite membrane. A polyvinylidene fluoride (PVDF) polymer membrane was synthesized using the phase inversion method and subsequently modified with MnFe-LDH nanoparticles. The structural, morphological, and physicochemical properties of the prepared materials were characterized using XRD, BET, FT-IR, FE-SEM, EDS, and contact angle analyses. Critical operational parameters influencing the adsorption process, such as dye concentration, adsorption time, and adsorbent dosage, were systematically studied and optimized using response surface methodology (RSM) based on central composite design (CCD). In addition, the pH of the solution was optimized as a single independent variable. The impact of each parameter on the removal efficiency of the dyes was thoroughly analyzed. Optimization studies identified the following optimal conditions: Adsorption time = 15 min, the amount of adsorbent = 0.015 g, pH = 5, TZ = 16 mg/L, and EB = 13 mg/L. Under these conditions, removal efficiencies of 94.74 % and 92.13 % were achieved for TZ and EB dyes, respectively. The adsorption behavior was best described by the Langmuir isotherm model, indicating monolayer adsorption on a homogeneous surface. Kinetic evaluations revealed that the adsorption processes adhered closely to pseudo-first-order kinetic models. This study provides valuable insights into the development and application of MnFe-LDHs/PVDF composite membranes, highlighting their potential as effective materials for mitigating dye pollution in wastewater treatment systems.