Chemistry
Samuel N. Ndung’u; Ruth N. Wanjau; Esther W. Nthiga
Abstract
The current study utilizes Silicon Nitride (Si3N4) as a novel adsorbent in evaluating its adsorptive ability for Congo red dyes from an aqueous solution. The adsorbent was prepared using extracted silica from sand and coffee husk biochar in an ammonia environment. The Si3N4 adsorbent was characterized ...
Read More
The current study utilizes Silicon Nitride (Si3N4) as a novel adsorbent in evaluating its adsorptive ability for Congo red dyes from an aqueous solution. The adsorbent was prepared using extracted silica from sand and coffee husk biochar in an ammonia environment. The Si3N4 adsorbent was characterized using a Field Emission Scanning Electron Microscope (FEI ESEM) which showed rod-like and fiber-like structures for α-Si3N4 and β- Si3N4, respectively. The SEM results also showed pores on the adsorbent surface before adsorption and a more rigid and restrained surface after adsorption. The adsorbent surface is hydroxylated in water to give important adsorption sites of silanolate ions (Si-O-) and silazane groups (Si2=NH2+) responsible for congo red (CR) dye removal. The adsorption process was investigated by batch mode. The maximum adsorption capacity (28.87 mg/g) was obtained at an optimal pH=1.00, agitation time (50 minutes), adsorbent dosage (25 mg), and initial concentration (50 mg/L). The Langmuir isotherm model was best fitted with equilibrium data with R2 > 0.9, showing that the adsorption was chemisorption in nature. The results revealed Si3N4 adsorbent as a potential adsorbent in textile dye wastewater treatment.
Chemistry
Abdullahi Muhammad Ayuba; Thomas Aondofa Nyijime; Safiyya Abubakar Minjibir; Fater Iorhuna
Abstract
Quantum functions were used to assess a theoretical investigation on mild steel's resistance to corrosion. To determine the stable geometry of the investigated compounds, TPE and PME, local density function B3LYP was optimized and simulated using DFT under restricted spin polarization DNP basis. The ...
Read More
Quantum functions were used to assess a theoretical investigation on mild steel's resistance to corrosion. To determine the stable geometry of the investigated compounds, TPE and PME, local density function B3LYP was optimized and simulated using DFT under restricted spin polarization DNP basis. The molecules' local and global reactivity, including their electronegativity (χ), dipole moment (μ), energy gap (ΔE), global hardness (η), global electrophilicity index (ω), energy of back donation (∆Eb-d), fraction of electron transfer (ΔN), and the (ω+) and (ω-) electron accepting and donating powers between the molecule and the iron, were all studied. The inhibition process was assumed to be a chemisorption interaction between the surface and the molecule based on the number of adsorption sites and the binding energy obtained from the process. This is because the molecules contain hetero-atoms, such as oxygen and methylene (-CH2-) functional groups. For PME and flourine for TPE, which serve as the focal point for the selectivity of electron donation and acceptance between the metal and the TPE and PME moieties.
