A promising modified polyvinyl chloride for adsorption of boron: Preparation, adsorption kinetics, isotherm, and thermodynamic studies

Abstract

AbstractA new promising N‐methyl‐D‐glucamine modified polyvinyl chloride via methyl glycinate linker (PVC‐MG‐NMDG) was designed to extract boron from tourmaline ore from the Sikait area in the South Eastern Desert of Egypt, which assays 10.43% B2O3. Specifications for PVC‐MG‐NMDG composite were executed successfully utilizing sundry approaches, such as FT‐IR, XPS, GC–MS, TGA, BET, EDX, 13C‐NMR, 1H‐NMR, ICP‐OES, and XRD, which assure an acceptable synthesis of PVC‐MG‐NMDG. Optimized factors like pH, agitation time, primary boron concentration, composite dose, co‐ions, eluting agents, and temperature have been improved. At ambient temperature, pH 9, 10 min of agitation, and 0.0138 mol/L boron ions (150 ppm), the PVC‐MG‐NMDG composite has a 25 mg/g maximal uptake. The extraction‐distribution isotherm modeling suggests that the Langmuir model, with a theoretical value of 25.38 mg/g, more closely matches the practical value of 25 mg/g than the Freundlich model. The adsorption kinetics of boron ions by PVC‐MG‐NMDG were predicted with high accuracy using a pseudo‐second order kinetic model, yielding a theoretical retention capacity of 27.93 mg/g. The extraction process was predicted, as shown by thermodynamic calculations, exothermic, spontaneous, and optimal extraction at low temperature; the thermodynamic factors controlling ΔS (−0.04 kJ/mol), ΔH (−13.74 kJ/mol), and ∆G values rise from −1.82 kJ/mol at 298 K to −0.19 kJ/mol at 338 K. Boron ions can be eluted from the overloaded composite by 0.5 M H2SO4 with a 95% efficiency rate. It was established that PVC‐MG‐NMDG composite reveals a worthy separation factor to most co‐ions and gives a good separation power. Boric acid with a boron content of 17.23% and purity of 98.56% can be obtained through alkali fusion with NaOH flux and subsequent adsorption using a PVC‐MG‐NMDG composite.Highlights A New modified polyvinyl chloride (PVC‐MG‐NMDG) was successfully prepared. The characteristics of new composite were verified via different techniques. The new composite reached its maximum boron absorption of 25 mg/g at 25°C. The extraction as an exothermic, spontaneous process at low temperature. The new composite has been applied to a real sample of Sikait tourmaline ore.