Recent advances in dyes uptake by microplastics in aquatic environments: Influencing factors and ecotoxicological behaviors

Understanding the adsorption mechanisms and interaction of dye pollutants and microplastics in natural water is vital to evaluating potential risks. This review article discusses the bibliometric analysis and the adsorption behavior of dyes to microplastics. The review also examined the impact of environmental (salinity, pH, and temperature) and physicochemical (particle size and active area) factors on dye uptake by microplastics. The maximum amount of Cyan dye adsorbed onto polyethylene microplastics was reported to be 2874.4 mg/g. Polystyrene (PS) microplastics exhibited the highest adsorption capacity for aniline (0.060 mg/g) due to its surface area of 0.7214 m2/g. In 50 % of dye uptake studies on microplastics, the equilibrium condition was reached within 24 h. However, in a few cases, equilibrium was achieved in 8 days. The desorption efficiency of malachite green in the simulated gastric fluid at high temperatures was 81.4 %. The concentration of dyes in the isotherm studies of their adsorption by microplastics varied widely (5–160 mg/L). According to the criterion of R2 > 0.95, the Langmuir isotherm demonstrates a better fit with the data in most of the studies. The lowest uptake of dyes was observed at a pH of 1.5 under the same conditions. Studies have shown that higher temperatures can increase the ability of microplastics to attract and release organic and inorganic pollutants. The potential ecological effects of ‘microplastic-dye’ on organisms and the methods for removing microplastics were investigated. This paper has provided data for the assessment of the potential risks of ‘microplastic-dye’ to aquatic organisms.