Techno-economics of coconut coir bioadsorbent utilization on free fatty acid level reduction in crude palm oil

Effective Removal of Selenium from Aqueous Solution Using Iron-Modified Dolochar: A Comprehensive Study and Machine Learning Predictive Analysis

Selenium (Se) is an essential micronutrient for human beings, but excess concentration can lead to many health issues and degrade the ecosystem. This study focuses on the removal of selenium from an aqueous solution using iron-doped dolochar. SEM, EDX, BET, XRD, FTIR, and Pzpc were conducted to determine the surface characteristics of iron-doped dolochar (FeD). The characterization of the adsorbent gave an insight into surface morphology, surface area (100 m2/g), average pore diameter (3.9 nm), and surface composition, which contributed to the Se adsorption. The pHzpc of the iron-doped adsorbent surface was found to be 7.02, which provided a broad range for effective Se adsorption. To detect the optimum parameters, the parametric influence on removal efficiency was conducted by varying pH, dosages, contact time, and initial concentration. The experiment achieved maximum selenium removal, ∼98 %, at low concentration, 10 g/L dosage, and low pH (2) within 90 min at room temperature. It fits the Langmuir better than the Freundlich isotherm (R2 = 0.99), indicating monolayer adsorption. It fitted well with pseudo-second-order kinetics. The experiment is a spontaneous, endothermic (ΔH0=9.22 kJ/mol) and high randomness (ΔS0 =45.37 kJ/mol) suggested by thermodynamic study. The adsorption was influenced by competing ions as follows: phosphate > sulfate > nitrate > manganese > aluminum> zinc > iron. A regression learner tool was used to compare different models using the experimental data that showed the best fit with the Gaussian Process Regression with RMSE =0.246, MSE = 0.061, and R2 = 0.99. Thus, it can be concluded that FeD is preferred as a better adsorbent for selenium removal from aqueous solutions and could produce 35.5% ROI, 21.5% IRR, and 24.59% BEP on FeD production.

Exploring the effective adsorption of polystyrene microplastics from aqueous solution with magnetically separable nickel/reduced graphene oxide (Ni/rGO) nanocomposite

Microplastics (MPs) are a potential threat to both humans and aquatic environment as they serve as carriers of various contaminants necessitating the development of reliable, efficient, and ecofriendly techniques to remove MPs from water. In this study, reduced graphene oxide (rGO) magnetized using nickel nanoparticles was utilized as a potent adsorbent for the effective removal of microplastics from water. The synthesized nickel/reduced graphene oxide (Ni/rGO) nanocomposite was characterized by X-ray diffraction (XRD), Raman spectra, vibrating sample magnetometer (VSM), scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX), thermogravimetric analysis, and Brunauer-Emmett Teller (BET) analysis. Magnetic Ni/rGO nanocomposite exhibited significant adsorption capability for polystyrene (PS) microspheres allowing the formation of PS-Ni/rGO complex which can be easily separated out using a magnet. The SEM images of PS-Ni/rGO complex confirmed the adsorption of PS microspheres onto the nano adsorbent due to hydrophobic interaction. The adsorbent demonstrated a maximum adsorption capacity of 1250 mg/g. The analysis of isotherm and kinetic models demonstrated that the adsorption mechanism conformed to the Langmuir isotherm and followed pseudo second order kinetics. This study paves a new pathway for the application of magnetically modified reduced graphene oxide for the expedient removal of microplastics from water with the ease of separation using a magnet. The adsorbent was recycled and reused for three times.

Extraction of lignin-containing nanocellulose fibrils from date palm waste using a green solvent

Lignin-containing nanocellulose (LNC) is a compelling alternative to traditional nanocellulose (NC), it offers enhanced yields and a reduction in the demand for toxic chemicals. This research involves the isolation of LNC from date palm waste using a green hydrolysis process and its subsequent characterization. The potential of using ionic liquids (ILs) as green solvents to isolate LNC has not yet been explored. Our findings suggest that 1-ethyl-3-methylimidazolium chloride ([Emim]Cl) can hydrolyze partially delignified and unbleached lignocellulose, achieving LNC synthesis. The obtained LNC showed a higher yield than its NC counterpart and exhibited rod-shaped fibers with nanoscale diameters and micrometer lengths, indicating a high aspect ratio. Dynamic Light Scattering (DLS) results indicate average particle sizes of 143.20 nm for NC and 282.30 nm for LNC, with a narrow particle size distribution conforming their monodisperse behavior. Thermogravimetric analysis and differential scanning calorimetry revealed high thermal stability (initial degradation temperature = 222.50 °C and glass transition temperature = 84.45°C) of LNC. Moreover, the obtained LNC fibers were crystalline (crystallinity index = 52.76 %). Their activation energy (124.95 kJ/mol) was determined using the Coats-Redfern method by employing eight solid-state diffusion models. Overall, this study motivates the use of ILs as green solvents to produce lignocellulose derivatives that are suitable for various applications.

Determination of Maximum Oil Yield, Quality Indicators and Absorbance Spectra of Hulled Sunflower Seeds Oil Extraction under Axial Loading

The present study aims to estimate the maximum oil yield of hulled sunflower seed samples in a uniaxial process under a load of 40 kN and speed of 4 mm/min. The oil samples were assessed for their quality parameters and spectra curves within the wavelength range of 325–600 nm. The results show that heating temperatures in the range of 40 °C to 80 °C increased the oil output; however, a maximum oil yield of 48.869 ± 6.023% with a minimum energy of 533.709 ± 65.644 J at the fifth repeated pressing was obtained from the unheated sample compared to the heated samples. The peroxide values ranged from 6.898 ± 0.144 to 7.290 ± 0.507 meq O₂/kg, acid values from 1.043 ± 0.166 to 1.998 ± 0.276 mg KOH/g oil and free fatty acid values from 0.521 ± 0.083 to 0.999 ± 0.138 mg KOH/g oil, which were within the recommended quality threshold. There were significant spectral differences among the oil samples. A single absorbance peak was observed at 350 nm for all oil samples, indicating low levels of pigment molecules in the oil. The study revealed the need for repeated pressings to recover the considerable residual oil remaining in the seedcake after the first pressing.