This study explores the potential of hydrochar derived from potato peels as a cost-effective option for efficient adsorption. Potato peel hydrochar (PPH) was produced via hydrothermal carbonization (HTC) with KOH activation at 200 °C for 2 h. The resulting hydrochar was then divided into three portions, two of which underwent mixing with urea followed by pyrolysis under N2 gas at 600 °C for 2 and 3 h, respectively, resulting in the formation of N-doped pyrochars (N-PPH.2 hrs and N-PPH.3 hrs). Characterization using Brunauer-Emmett-Teller (BET), Scanning Electron Microscope (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) revealed distinctive properties. The results showed that nitrogen atoms were effectively incorporated into the pyrochar, increasing significantly from 3.7 to 8.3% and then to 45.6% as new nitrogen compounds. This modification impacted the acidity and basicity of the chemical surfaces of the pyrochar. The N-doped pyrochar, with a particle sizve of N-doped compounds at 296.11 nm, demonstrated the most efficient adsorption of Congo red (CR). This efficiency was achieved through various mechanisms, including pore filling, Lewis acid-base interaction, hydrogen bonding, and π–π interaction. The presence of highly available functional groups, primarily pyridinic-N, pyrrolic-N, and graphitic-N, further enhanced the adsorption capacity. The highest adsorption capacities were observed at 310 mg g−1 for N-PPH-2Hr and 400 mg g−1 for N-PPH-3Hr, respectively. Increased temperature and CR concentration correlated positively with enhanced adsorption, following Freundlich isotherm and pseudo second-order kinetics. Further, the results indicate that the adsorption of Congo red by the prepared chars is endothermic, increases disorder, and is a spontaneous process. This study highlights the cost-effectiveness of agro-industrial waste-derived chars for Congo red removal, highlighting economic and environmental benefits.

This study aimed to investigate the potential of potato peel waste powder as a biomass feedstock for hydrothermal carbonization to produce hydrochar, which could be used as an adsorbent for water treatment. An autoclave was used at 200 °C for 25 h to prepare potato peel hydrochar from potato peel waste powder and compared their physicochemical properties using various characterization techniques. The results showed that potato peel hydrochar had a higher specific surface area and adsorption capacity for Congo red than potato peel waste powder, making it a viable adsorbent for water treatment. The experimental data were well-fitted with the Freundlich isotherm and pseudo-second-order kinetic models suggesting that the adsorption process at the solid/solution interface is spontaneous, endothermic, and more disordered. The study highlights the potential of waste biomass, such as potato peel, to produce hydrochar as an effective and sustainable adsorbent for water treatment.

AlxIn1-xSb nanocrystals have been studied using ab-initio calculations. The electronic properties were simulated using different core atoms ( usually 8, 16, 54, and 64). The calculations used showed that the concentration increment affects the crystal size. All calculations were done using Gaussian 03 code with Hartree-Fock calculation with the GGA approximation