Commercial flakes of graphite were prepared into functionalized graphene oxide (GO) by chemical treatment. After the exfoliation and intercalation of graphene into functionalized graphene oxide that formed stable colloidal dispersion in polar aprotic solvent, the reduction process was undertaken by continuous stirring with hydrazine hydrate. The reduced material was characterized by X‐ray diffraction (XRD), attenuated total reflectance (ATR) FT‐IR, ultraviolet visible (UV‐vis), atomic force microscopy (AFM) and Raman spectroscopy which confirm the oxidation of graphite and reduction of graphene oxide into graphene sheet.

Plain polyvinyl alcohol (PVA) nanofibres and novel polyvinyl alcohol benzene tetracarboxylate nanofibres incorporated with strontium, lanthanum and antimony ((PVA/Sr-TBC), (PVA/La-TBC) and (PVA/Sb-TBC)), respectively, where TBC is benzene 1,2,4,5-tetracarboxylate adsorbents, were fabricated by electrospinning. The as-prepared electrospun nanofibres were characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Only plain PVA nanofibres followed the Freundlich isotherm with a correlation coefficient of 0.9814, while novel nanofibres (PVA/Sb-TBC, PVA/Sr-TBC and PVA/La-TBC) followed the Langmuir isotherm with correlation coefficients of 0.9999, 0.9994 and 0.9947, respectively. The sorption process of all nanofibres followed a pseudo second-order kinetic model. Adsorption capacity of novel nanofibres was twofold and more compared to that of plain PVA nanofibres. The thermodynamic studies: apparent enthalpy (ΔH°) and entropy (ΔS°), showed that the adsorption of Pb(II) onto nanofibres was spontaneous and exothermic. The novel nanofibres exhibited higher potential removal of Pb(II) ions than plain PVA nanofibres. Ubiquitous cations adsorption test was also investigated and studied.

Ternary layered double hydroxide (Co–Zn–Al LDH) intercalated with carbonate was synthesised via a simple co-precipitation method at pH ≥10. It was characterised using the Fourier transform infrared (FTIR) spectrometer, X-ray diffractometer (XRD), surface area and porosity analyser, Thermo-gravimetric/differential thermal analysis (TGA–DTA), and Scanning Electron Microscope (SEM). The Pb(II) adsorption properties, mechanism, and possible reuse of the LDH were also investigated by the batch technique. The characterisation results showed the presence of hydroxyl group as well as the intercalated carbonate anions within the well-defined LDH crystal structure. The TGA-DTA results confirmed the presence of these anionic groups which were liberated from the structure at ≈200 and 300°C, respectively. The LDH-specific surface area, pore diameter and width are 54.0 m²/g, 41.3 and 25.1 nm, respectively. Adsorption results showed that Pb(II) equilibrium could be achieved in 120 min, and adsorption increased with concentration and temperature. A Pb(II) adsorption capacity of 130.34 mg/g was reached for this LDH, and the adsorption process was spontaneous, endothermic and mainly electrostatic with most of the adsorption occurring within the pores. Desorption test suggested that approximately 90% of the adsorbed Pb(II) could be desorbed; hence, the Co–Zn–Al–CO₃ LDH may be reused.

Helical carbon fibers (HCFs) have been widely studied due to their unique helical morphology and superior properties, which make them efficient materials for several potential applications. This review summarizes the past and current advancement on the synthesis of HCFs. The review focuses and discusses synthesis strategies and effect of experimental parameters on the growth of HCFs. The effect of preparation method of catalyst, catalyst nature, catalyst composition, catalyst size, catalyst initial and final shape, reaction temperature, reaction time, carbon source, impurities, and electromagnetic field on the growth of HCFs is reviewed. We also discuss the growth mechanism for HCFs and the synthesis of HCFs related materials. Finally, we conclude with a brief summary and an outlook on the challenges and future prospects of HCFs.

The sorption of Pb²⁺from solution by polyvinyl chloride waste was investigated. The morphological features of the polymer sample were studied using the energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), and the Fourier transform infrared spectroscopy (FTIR). Equilibrium, kinetic, and thermodynamic batch adsorption experiments were carried out by the concentration, time, and temperature effects, respectively. The morphological image of the polymer showed irregular small size particles which indicated a high surface area and porosity that facilitated sorption. The adsorption studies recorded relatively rapid uptake of Pb²⁺by the polymer which was mainly diffusion controlled and followed a second order kinetic process. The thermodynamic studies suggested relatively low temperature (low energy) favoured sorption which was exothermic with a physisorption mechanism.