Amaranthus hybridus waste solid biofuel: comparative and machine learning studies.

The diminishing supply of fossil fuels, their detrimental environmental effects, and the challenges associated with the disposal of agro-waste necessitated the development of renewable and sustainable alternative energy sources. This study aims at developing bio-briquettes from Amaranthus hybridus waste, with cassava starch as a binder; both are agricultural wastes. Before and following delignification, alkali-treated Amaranthus hybridus (TAHB) and untreated (UAHB) briquettes were evaluated in terms of combustion and physicochemical parameters. FTIR and SEM were utilized to monitor the morphological transformation and bond restructuring of TAHB and UAHB samples. EDXRF was used to assess the Potential Toxic Elements (PTEs) composition and environmental friendliness of both TAHB and UAHB. Furthermore, Adaptive Neuro-Fuzzy Inference System (ANFIS) and fuzzy c-means (FCM) clustering machine learning models were used to optimize the production process and predict the efficiency of bio-briquettes. After delignification, a lower lignin value of 11.47 ± 0.00% in TAHB compared to 12.31 ± 0.01% (UAHB) was recorded. Calorific values of 10.43 ± 0.25 MJ kg-1 (UAHB) and 12.53 ± 0.30 MJ kg-1 (TAHB) were recorded at p < 0.05. EDXRF results showed a difference of 0.016% in Pb concentration in both samples. SEM reveals morphological restructuring, while FTIR reveals a 4 cm-1 difference in the C-O stretch. The root mean square error (RMSE), mean absolute percentage error (MAPE), and mean absolute error (MAE) gave values of 0.0249, 2.104, and, 0.0249; (MAE, training) and 0.0223 (MAE, testing) respectively. This shows that the model's predictions match the reality, thereby suggesting a strong agreement between the predicted and experimental data. The finding of this study shows that delignification-disruption improved the solid biofuel's ability to burn cleanly and sustainably.

Thermally modified nanocrystalline snail shell adsorbent for methylene blue sequestration: equilibrium, kinetic, thermodynamic, artificial intelligence, and DFT studies.

In recent years, the quest for an efficient and sustainable adsorbent material that can effectively remove harmful and hazardous dyes from industrial effluent has become more intense. The goal is to explore the capability of thermally modified nanocrystalline snail shells (TMNSS) as a new biosorbent for removing methylene blue (MB) dye from contaminated wastewater. TMNSS was employed in batch adsorption experiments to remove MB dye from its solutions, taking into account various adsorption parameters such as contact time, temperature, pH, adsorbent dosage, and initial concentration. SEM, EDS, XRD, and FTIR were used to characterize the adsorbent. The study further developed and adopted adaptive neuro-fuzzy inference system (ANFIS) and density functional theory (DFT) studies to holistically examine the adsorption process of MB onto the adsorbent. EDX and FTIR confirm the formation of CaO with a sharp peak at 547 cm-1, and C-O and O-H are present, as well. SEM and XRD show an irregularly shaped highly crystalline nanosized (65 ± 2.81 nm) particle with a lattice parameter value of 8.611617 Å. The adsorption efficiency of 96.48 ± 0.58% was recorded with a pH of 3.0 and an adsorbent dose of 10 mg at 30 °C. The findings from the study fit nicely onto Freundlich isotherms, with Qm = 31.7853 mg g-1 and R2 = 0.9985. Pseudo-second-order kinetics recorded the least error value of 0.8792 and R2 = 0.9868, thus indicating chemisorption and multilayer adsorption processes. The exothermic and spontaneous nature of the adsorption process are demonstrated by ΔH° and ΔG°. The performance of the ANFIS-based prediction of removal rate, which was demonstrated by a root mean square error (RMSE) value of 2.2077, mean absolute deviation (MAD) value of 1.1429, mean absolute error (MAE) value of 1.8786, and mean absolute percentage error (MAPE) value of 2.0178, revealed that the ANFIS model predictions and experimental findings are in good agreement. More so, DFT provides insights into the molecular interactions between MB and the adsorbent surface, with a calculated adsorbate-adsorbent binding affinity value of -1.3 kcal mol-1, thus confirming the ability of TMNSS for MB sequestration. The findings of this study highlight the promising potential of thermally modified nanocrystalline snail shells as sustainable and efficient adsorbents for MB sequestration.

Electronic and optical properties' tuning of phenoxazine-based D-A2-π-A1 organic dyes for dye-sensitized solar cells. DFT/TDDFT investigations.

Modulation of molecular features of metal free organic dyes is important to present sensitizers with competing electronic and optical properties for dye sensitized solar cells (DSSCs). The D-A2-π-A1 molecular design based on phenothiazine skeleton (D) connected with benzothiadiazole (A2) linked with furan π-spacer and acceptor unit of cynoacrylic acid (A1) were fabricated and examined theoretically for possible use as DSSCs. Density functional theory (DFT) and time dependent density functional theory TDDFT were used to study the effect of additional donors on the photophysical properties of the dyes. Eight (8) different donor subunits were introduced at C7 of phenoxazine based dye skeleton to extend the π-conjugation, lower HOMO-LUMO gap (Eg) and improve photo-current efficiency of the dye sensitizer. All the dye sensitizers (except P3 and P4) exhibited capability of injecting electrons into the conduction band of the semiconductor (TiO2) and regenerated via redox potential (I-/I3 -) electrode. Attachment of 2-hexylthiophene (P2) remarkably lowered the Eg, extended π-electron delocalization, hence, gives higher absorption wavelength (λmax) at 752 nm. The donor subunit containing 2-hexylthiophene (P2) presented the best chemical hardness, open circuit voltage (Voc), and other comparable electronic properties, making P2 the best DSSC candidate amongst the optimized dyes. The reported dyes would be interesting for further experimental research.

Synthesis and characterization of Zn-Doped hydroxyapatite: scaffold application, antibacterial and bioactivity studies.

In this study, the antimicrobial and scaffold of zinc-substituted hydroxyapatite, (Zn-HAp) synthesized via chemical co-precipitation technique was investigated. The structure of the synthesized Zn-HAp was investigated with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Scanning electron microscope (SEM), Energy dispersive X-spectroscopy (EDAX), transmission electron microscope (TEM), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Bioactivity study was performed in simulated body fluid (SBF), while the antimicrobial activity was studied using disc diffusion method. The XRD structure revealed that Zn ion incorporation up to 10% led to the second phase hydroxyapatite (HAp) formation, while higher concentration diminished the apatite structure. The presence of phosphate ions, carbonates ions, and hydroxyl groups in the apatite powder was ascertained by the FT-IR evaluation. SEM evaluation showed that the apatite contains fine particles with nearly round shape with interconnected pores and decreasing Ca/P ratio with increasing Zn ion concentration. TEM results showed particulate polycrystalline apatite with crystallite size ranging from 68 nm in pure HAp to 41 nm in 20% Zn-doped HAp indicating a decrease in the crystal size with increasing Zn ion in the samples. The bioactivity study showed spherical deposition around the porous region of the scaffold HAp suggesting the growth of apatite in SBF media after 7 days of incubation, while antibacterial activity studies showed zones of inhibition with an increase in zinc ions concentrations.

Biowaste-Derived Hydroxyapatite for Effective Removal of Reactive Yellow 4 Dye: Equilibrium, Kinetic, and Thermodynamic Studies.

This study examines the application of poultry eggshell (PES) as a source of calcium for the synthesis of hydroxyapatite (HA) via annealation. The synthesized powder (poultry eggshell hydroxyapatite (PESHA)) was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), EDAX, and transmission electron microscopy (TEM) analytical techniques. This powder was used for adsorptive removal of the Reactive Yellow 4 (RY4) dye in a batch process. Results from morphological analysis by SEM and TEM revealed that the microstructure of the apatite is made up of needle-rod-like particles with the length of 15-60 nm, breadth of 4-6 nm, and crystallite size of 86.32 nm. EDAX revealed that HA has Ca/P ratio of 1.63, indicating a nonstoichiometric apatite, whereas XRD analysis presented it as a pure monophasic hydroxyapatite powder. Fourier Transform Infrared (FTIR) spectroscopy indicated that the adsorption is due to the electrostatic interaction between the functional groups of the dye and those on the apatite surface. The maximum adsorption capacity (Q max) of 127.9 mg g-1 was obtained for the adsorption process, whereas the pseudo-first-order model with R 2 > 0.99 best described the adsorption mechanism. Furthermore, the thermodynamic studies revealed that the adsorption process was exothermic and spontaneous in nature with ΔH and ΔS values of 120.79 kJ mol-1 and 0.395 kJ mol-1 K-1, respectively. Thus, hydroxyapatite fabricated from the poultry waste of eggshell can be effectively utilized as an excellent nontoxic and cheap adsorbent for the removal of RY4 dye from aqueous medium.

Photophysicochemical behaviour and antimicrobial properties of monocarboxy Mg (II) and Al (III) phthalocyanine-magnetite conjugates.

Asymmetric Mg (II) or Al (III) phthalocyanine (containing a COOH group and 3-pyridylsulfanyl units) was conjugated via an amide bond to amino functionalized magnetic nanoparticle (AIMN) to form MgPc-AIMN or AlPc-AIMN conjugate, and characterized. The photophysicochemical behaviour of the phthalocyanine-AIMN conjugates was investigated and compared to the asymmetric Pcs and to the simple mixture of Pc with AIMNs without a chemical bond, (MPc-AIMN (mixed)). The directed covalent linkage of AIMNs to the asymmetrical metallopthalocyanines afforded improvements in the singlet oxygen (ФΔ) and triplet state quantum yield (ФT) as well as singlet oxygen lifetimes for the MPcs-AIMN-linked conjugates compared to MPc-AIMN (mixed) and MPcs alone. The asymmetric phthalocyanines and their conjugates showed effective antimicrobial activity against Escherichia coli bacteria under illumination.

Photophysicochemical behavior and antimicrobial activity of dihydroxosilicon tris(diaquaplatinum)octacarboxyphthalocyanine.

Platination of dihydroxosilicon octacarboxyphthalocyanine (OH)2SiOCPc was successfully carried out to give dihydroxosilicon tris(diaquaplatinum)octacarboxyphthalocyanine (OH)2SiOCPc(Pt)3 conjugate. Slight blue shifting of the absorption spectrum of (OH)2SiOCPc(Pt)3 was observed on conjugation with platinum. Comparative photophysicochemical behavior and antimicrobial photo-activities of (OH)2SiOCPc(Pt)3 conjugate with (OH)2SiOCPc or Pt nanoparticles revealed that the heavy atom, Pt on the periphery of the phthalocyanine significantly enhanced its singlet oxygen generation with a quantum yield of 0.56 obtained for the (OH)2SiOCPc(Pt)3 conjugate. The (OH)2SiOCPc(Pt)3 conjugate showed highest antimicrobial activity towards Candida albicans and Escherichia coli compared to (OH)2SiOCPc and Pt nanoparticles alone under illumination.