Removal of toxic methylene blue dye from aqueous solutions by adsorption technique using magnetic loaded tea waste and its sodium alginate composite microspheres
Environmental Monitoring and Assessment, vol.197, no.6, 2025 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 197 Issue: 6
- Publication Date: 2025
- Doi Number: 10.1007/s10661-025-14107-1
- Journal Name: Environmental Monitoring and Assessment
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, ABI/INFORM, Agricultural & Environmental Science Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, CAB Abstracts, Compendex, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, Greenfile, Pollution Abstracts, Public Affairs Index, Veterinary Science Database, Civil Engineering Abstracts
- Keywords: Adsorption, Sodium alginate, Tea waste-magnetite
- Yıldız Technical University Affiliated: Yes
Abstract
This study presents the utilization of Fe3O4-doped black tea waste (TW) as an efficient, sustainable, and cost-effective adsorbent for the extraction of MB dye from wastewater, alongside the formulation of composite microbeads created by incorporating varying ratios of the black tea-magnetite mixture into sodium alginate (SA), a natural biopolymer. The characterization of composite microbeads was performed using FTIR-ATR, SEM, EDX, and pHpzc analyses. The surface charge of the adsorbent surface was determined as 6.43 from pHpzc. From the optimum condition studies, the contact time (60 min), adsorbent dosage (0.1 g/50 mL), and the initial pH (≅ 7) were determined. The raw data were utilized in various non-linear isotherm and kinetic models. The correlation coefficients and error functions indicated that the Langmuir model is the most suitable isotherm model for the adsorption process, with a maximum adsorption capacity of 41.28 mg g−1 for the SA/TW/Fe3O4/30 composite microspheres at 298 K. The kinetic and error results indicated that the process adhered to a pseudo-second-order kinetic model. The thermodynamic characteristics indicated that the adsorption process was spontaneous (ΔGo=-25.09 kJ mol−1) and endothermic (ΔHo=+9.03 kJ mol−1). Moreover, reusability investigations indicated that the composite microbeads can be utilized multiple times. Following the tenth cycle, the adsorption efficiency fell by 32.33%, resulting in a value of 51.23%. The findings indicate that the developed unique, sustainable, and cost-effective composite microbeads serve as a prospective and highly efficient adsorbent for the elimination of cationic contaminants from wastewater.