Rapid and effective removal of heavy metal ions from aqueous solution using nanostructured clay particles

Natural mineral clays were extracted from the Syahkalahan mine and used as adsorbent matrices with the aim of removing lead ions (Pb) from drinking water. In this study, the chemical structure, surface morphology, and surface area of prepared clays were characterized using various techniques, including inductively coupled plasma-mass spectrometry, powder X-ray diffraction, field emission scanning electron microscopy (FE-SEM), and Brunauer–Emmett–Teller surface porosity analysis. Characterization results revealed that silica is the dominant chemical component of the clay. FE-SEM images of clay samples confirmed that the average size of clay’s particles is in the nanoscale range. The results for two different clays showed ion removal efficiency of > 92% under the following experimental conditions: clay weight = 1 g, [Pb(II)] =100 ppm, pH = 7, and time = 120 min. Additionally, for the clay samples exhibiting the best removal efficiency, the ion removal efficiency was studied as a function of reaction parameters such as pH, and concentration of both adsorbent and metal ions. To evaluate the adsorption kinetics and mechanism of ion adsorption, kinetic modeling and isotherm models (Langmuir and Freundlich) were performed under the optimized conditions. Based on the fitting analysis, it can be inferred that the adsorption kinetic follows a pseudo-first-order model and the Langmuir isotherm accurately describes the adsorption mechanism of Pb(II) ions on the clays’ surface. These findings further highlight that these inexpensive natural clays can be used as excellent matrices for the adsorption of heavy metal ions in various water treatment systems

Transforming Waste Clamshell into Highly Selective Nanostructured Catalysts for Solvent Free Liquid Phase Oxidation of Benzyl Alcohol

High yield production of benzaldehyde in the solvent-free oxidation of benzyl alcohol by using green catalysts is highly desirable. In this work, calcium hydroxide derived from waste clamshell was used as low-cost and environmentally friendly catalyst support (CaSUP) for Pd and V nanoparticles. The physicochemical properties of the catalysts were analyzed using X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) technique, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The catalytic oxidation of benzyl alcohol to benzaldehyde was studied in a liquid phase reaction by using H2O2 as an oxidizing agent. The effects of catalyst loading, the molar ratio of hydrogen peroxide to benzyl alcohol, temperature and reaction duration were investigated. In the optimized conditions, Pd nanoparticles supported on clamshell-derived supports displayed excellent catalytic conversion (88%) and selectivity to benzaldehyde (89%). Furthermore, the catalyst can be effectively reused without a significant loss in its activity and selectivity. The high yield and stability can be related to the structural and basic properties of the catalyst. These results provide important insights into the benzyl alcohol oxidation process for industrial applications

Ni-Based Composites from Chitosan Biopolymer a One-Step Synthesis for Oxygen Evolution Reaction

Cost-efficient and sustainable electrocatalysts for oxygen evolution reaction (OER) is highly desired in the search for clean and renewable energy sources. In this study, we develop a new one-step synthesis strategy of novel composites based on Ni and molybdenum carbide embedded in N- and P-dual doped carbon matrices using mainly chitosan biopolymer as the carbon and nitrogen source, and molybdophosphoric acid (HMoP) as the P and Mo precursor. Two composites have been investigated through annealing a mixture of Ni/chitosan and HMoP with two unlike carbon matrices, melamine and graphene oxide, at a high temperature. Both composites exhibit similar multi-active sites with high electrocatalytic activity for OER in an alkaline medium, which is comparable to the IrO2 catalyst. For this study, an accurate measurement of the onset potential for O2 evolution has been used by means of a rotating ring-disk electrode (RRDE). The use of this method allows confirming a better stability in the chitosan/graphene composite. This work serves as a promising approach for the conversion of feedstock and renewable chitosan into desired OER catalysts