Values Of Thermodynamic Parameters Research Articles

Removal of phosphate from wastewater using zirconium/iron embedded chitosan/alginate hydrogel beads: An experimental and computational perspective

Adsorptive removal of phosphate plays a crucial role in mitigating eutrophication. Herein, the Zr/Fe embedded chitosan/alginate hydrogel bead (Zr/Fe/CS/Alg) is reported as an effective phosphate adsorbent. This polymer nanocomposite is synthesized by the in-situ reduction of the metals on the polymer matrix. The synthesized adsorbent was characterized by the FTIR, SEM-EDX, TGA, BET, and XPS. The adsorbent showed a maximum phosphate adsorption capacity of 221.72 mg/g at pH 3. The experimental data fit well with the Freundlich isotherm and pseudo-second-order kinetics model, indicating a heterogeneous multilayer surface formation and a chemisorption-dominated adsorption process. Density Functional Theory (DFT) and Monte Carlo (MC) calculations revealed high negative adsorption energy due to the chemisorption of phosphate on the adsorbent. Hence, the major interactions such as electrostatic attraction, hydrogen bonding, and inner-sphere complexation of phosphate adsorption and Zr/Fe/CS/Alg hydrogel beads were investigated from the experimental and computational analysis. The negative values of thermodynamic parameters indicated a spontaneous, exothermic, and less random adsorption process. The synthesized adsorbent exhibited excellent selectivity toward phosphate and maintained 73 % efficiency after six adsorption/desorption cycles. The Zr/Fe/CS/Alg hydrogel beads reduced the phosphate concentration in real wastewater samples from 19.02 mg/L to 0.985 mg/L, suggesting that these nanocomposite hydrogel beads could be a promising adsorbent for real-world applications.

Computational Study of the Formation of Atmospheric Aerosol Precursors Under Ambient Conditions: A Case Study of the Interaction Between Sea Salt, Water, and Sulfuric Acid Molecules

ABSTRACTCluster formation has significant implications in atmospheric science and environmental chemistry. These clusters are characterized by complex interactions between their constituents, which influence their structure, stability, and growth. Experimental investigations are difficult for the initial stages of prenucleation cluster formation, which leads to larger aerosols. To understand the formation of clusters, the interactions between sea salts (NaCl, KCl, and MgCl2), water, and sulfuric acid molecules have been investigated. Each step has been comprehensively examined and thermodynamic parameters have been computed using DLPNO‐CCSD(T)/CBS//M06‐2X/6‐311++G(3df,3pd) to find the stabilities of the molecular complexes. Among all complexes, the binding energies of cluster (SS)1(W)1(SA)3 are found to be the lowest due to the formation of HCl, hydrogen bonding, and weak van der Waal forces. Sea salts have shown a more favorable interaction with H2SO4 compared to H2O molecules. The addition of H2SO4 increases the reactivity of the cluster (SS)1(W)n, while the addition of H2O molecules reduces the reactivity of the cluster (SS)1(SA)n. However, further addition of H2SO4 or H2O to the existing cluster (SS)1(W)n(SA)n increases the free energy of formation. Furthermore, the influence of temperature was also investigated, suggesting that complex formation is slightly more favorable at lower temperatures than at higher temperatures. The negative values of thermodynamic parameters indicate, that these complexes are spontaneous and exothermic over the colder regions.

Orange Peels as Activated Carbon Charcoal For Cu (II) Ions Elimination From Water Sources

Objectives: The goal of this work is to create inexpensive Orange Peel Activated Carbon (OPAC) for the environmentally friendly to eliminate of Cu (II) from its aqueous solution. Methods: activated carbon made by calcining orange peels at 500°C to cause them to burn. Methods: The samples were characterized using FTIR, transmission electron microscopy, and nitrogen adsorption-desorption. Cu (II) was adsorbed in a batch procedure utilizing 0.25 g of (OPAC) and 100 mL of solution with varying beginning concentrations ranging from 20–80 mg/L. The investigation focused on the effects of variables pH, temperatures, concentrations, dosages, and times on the adsorption capacity. Thermodynamic parameters were computed, adsorption kinetics were assessed using pseudo-first and pseudo-second-order were computed models, and the adsorption isotherms were fitted using the Langmuir and Freundlich models. Findings: The stretching of the hydroxyl groups is shown by peaks at 3100 and 4000 cm-1 as well as the 3300–3800 cm-1 region in the FTIR. Findings: the functionalized (OPAC). N2 adsorption isotherm revealed a hysteresis loop in the p/p0 region between 0.2 and 1. The surface area of obtained mesoporous OPAC was 0.99 nm. The maximum adsorption capacity (79.056 mg/g). Removal of Cu (II) was 99%. The adsorption process was spontaneous and less random, as indicated by the negative values of thermodynamic parameters (∆S° -14.0, ∆H°-54.76, and ∆G°-60.36 kJ.mol-1). According to the findings, orange peel has a high surface area and is highly porous, which allows it to effectively remove over 99% of harmful heavy metals from water sources. Novelty: The study proves that orange peel can be effectively used as one of the best-quality, reasonably priced, readily available, eco-friendly bio-sorbents that is also beneficial to the economy in the long run. Keywords: Orange peel, Cu (II), Adsorption, Kinetic, Thermodynamic, IFTR

Insights into the adsorption of thiophene and fluorinated-thiophenes on the Mg4O4 cluster: a quantum chemical investigation

In this work, the adsorption of thiophene on the Mg4O4 cluster was examined at the LC-ωPBE/6-311G(d,p) level of theory. The influence of replacing hydrogen atoms of thiophene with fluorine atoms was considered. The comparison of relative stabilities of possible isomers indicated most stable isomers were 3-FT … Mg4O4, 3,4-DFT … Mg4O4, 2,3,4-TFT … Mg4O4 structures in the mono, di and tri-fluorinated thiophenes, respectively. Corrected adsorption energy and thermodynamic parameter values of these systems were evaluated and the substituent effect on the adsorption was explored. 2-FT … Mg4O4, 3,4-DFT … Mg4O4, 2,3,4-TFT … Mg4O4 structures indicated the most significant adsorptions in the mono, di and tri-fluorinated thiophenes, respectively. Electrophilicity-based charge transfer (ECT) was employed to illustrate charge transfer between aromatic systems and the Mg4O4 cluster. Quantum theory of atoms in molecule (QTAIM) and interaction region indicator (IRI) were used to deeply investigate two fragments.

Potassium permanganate-modified eggshell biosorbent for the removal of diclofenac from liquid environment: adsorption performance, isotherm, kinetic, and thermodynamic analyses.

This study assess how well diclofenac (DCF) can be separated from aqueous solution using potassium permanganate-modified eggshell biosorbent (MEB). The MEB produced was characterised using XRD, FTIR, and SEM. Batch experiments were conducted to examine and assess the impact of contact time, adsorbent dosage, initial concentration, and temperature on the adsorption capacity of the MEB in the DCF sequestration. The best parameters to obtained 95.64% DCF removal from liquid environment were 0.05g MEB weight, 50mg/L initial concentration, and 60min contact time at room temperature. The maximum DCF sequestration capacity was found to be 159.57mg/g with 0.05g of MEB at 298K. The adsorption isotherm data were more accurately predicted by the Freundlich model, indicating a process of heterogeneous multilayer adsorption. The results of the kinetic study indicated that the pseudo-second-order kinetic models best matched the experimental data. The findings revealed that the dynamic of DCF entrapment is largely chemisorption and diffusion controlled. Based on the values of thermodynamic parameters, the process is both spontaneous and endothermic. The primary processes of DCF sorption mechanism onto the MEB were chemical surface complexation, hydrogen bonding, π-π stacking, and electrostatic interactions. The produced MEB showed effective DCF separation from the aqueous solution and continued to have maximal adsorption capability even after five regeneration cycles. These findings suggest that MEB could be highly efficient adsorbent for the removal of DCF from pharmaceutical wastewater.

Thermodynamics of micellization of octyltrimethylammonium bromide in 1,2-propanediol-water mixtures at temperatures from (293.15 to 308.15) K

The micellar properties of octyltrimethylammonium bromide (C8TAB) in both water and aqueous solutions of 1,2-propanediol have been investigated using accurate measurements of density, sound velocity, and surface tension in the temperature range between 293.15 and 308.15 K. The critical micelle concentration, CMC, the ionization degree, β, the standard thermodynamic parameters of micellization: free energy, ΔmicG°, enthalpy, ΔmicH°, entropy, ΔmicS° and the free energy of transfer, ΔtrG°, of the surfactant octyltrimethylammonium bromide in both water and 1,2 propanediol aqueous solution were evaluated from the experimental results.The CMC of the surfactant increases as the concentration of 1,2-propanediol increases, while the temperature does not exert important changes within the range considered.The value of the micellization thermodynamic parameters suggests that adding 1,2-propanediol makes the micellization process less favorable.The thermodynamic functions of transfer were calculated. The values of the free energy of transfer are small and positive and increase as the diol concentration increases confirming that the transfer of the surfactant from the bulk into the micelle is less favorable.

Removal of the bemacid blue E-TL using granular activated carbon from abundant biomass: adsorption isotherm, thermodynamic and kinetic studies

In this work, we were interested in the adsorption of an acid dye, Bemacid Blue E-TL by granular activated carbon based on olive stones. To shed light on the adsorption process, batch experiments were performed to study the effect of operating parameters on the adsorption process such as equilibrium time, GAC dose, pH, initial dye concentration, and temperature. The experimental results showed that the adsorption of the dye Bemacid Blue E-TL by GAC based on olive stones depends on the equilibrium time at 8 hours, the pH is 2 of the solution and the dose is 5 g.L-1. To explain the adsorption equilibrium, the experimental values were examined by Langmuir, Freundlich, and Temkin models. The equilibrium is perfectly described by the Langmuir model whose correlation coefficient is higher than 0.99. The maximum retained quantity of the Bemacid Blue E-TL is 55.6 mg.g-1. Different kinetic models such as pseudo-first order, pseudo-second order, and the intraparticle diffusion equation were used to evaluate the adsorption kinetics. The results of the kinetic modeling showed that the pseudo-second order fitted the data well, with a high coefficient of determination (R2 > 0.99) and intra-particle diffusion is not the only rate-limiting step. The thermodynamic parameter values enthalpy (ΔH°), entropy (ΔS°), and energy change (ΔG°) show that the adsorption processes are endothermic and spontaneous. The various results obtained are promising and encouraging to consider a more comprehensive study with the objective of showing that the adsorbent chosen for this study is effective and could be used as a low-cost adsorbent for acid dye removal.

Catalytic pyrolysis of pine needles using metal functionalized spent adsorbent derived catalysts: Kinetics, thermodynamics and prediction modelling using artificial neural network (ANN) approach

The current study was indented towards the evaluation of synergism of spent aluminum hydroxide nanoparticle (AHNP) adsorbent derived catalysts in the degradation of pine (Pinus roxburghii) needles through kinetics and thermodynamics analysis. Distinct kinetic (such as activation energy and pre-exponential factors) and thermodynamic (such as entropy, enthalpy, and Gibbs free energy) parameters were estimated through isoconversional (OFA and KAS) models. The study also aimed to envisage the reaction mechanism for all the distinct processes via Criado z master plots. Results illustrated the significant impact of all the different AHNP-derived catalysts in easing up the biomass degradation process. The KAS method evaluated the average activation energy for non-catalytic degradation as 130.01 kJ/mol, while the values changed to 120.95, 121.69, 125.99, 148.47 and 127.37 kJ/mol for Ni/AO, Fe/AO, Cu/AO, Zn/AO and Mo/AO catalyzed degradation, respectively. Amongst all, nickel (Ni/AO) and iron-doped (Fe/AO) catalysts brought the highest reduction in activation energy owing to the provision of strong acidic sites, high specific surface area, and better metal dispersion; subsequently leading to the increased rate of molecular scission and cracking reactions. Values of pre-exponential factor and thermodynamic parameter also displayed the positive impact of catalysts in terms of lowering down the molecular collisions, enthalpy, and disorderness of the system. Furthermore, artificial neural network (ANN) was also employed for the prediction of the biomass degradation where high regression (∼0.99) as well as low mean squared error (<10−5) illustrated the accurate prediction of complex biomass degradation by the ANN technique. Thus, the waste AHNP-derived catalysts have significant potential to be employed for the catalytic pyrolysis of pine needles together with aiding the cost-competitiveness, environmental sustainability, and renewability of the process.

Chitosan-coated coconut shell composite: A solution for treatment of Cr(III)-contaminated tannery wastewater

BackgroundTannery industry generates a large amount of Cr(III)-contaminated wastewater daily. Unless properly treated, not only this effluent contaminates the water body, but also damages the environment and threatens public health. This batch study investigates the feasibility of chitosan-coated coconut shells as a low-cost material for removing Cr(III) from tannery wastewater. Both chitosan and coconut shell (CS) waste are abundantly available from local agricultural and fishery industries. MethodsTo enhance its treatment performance for Cr(III) removal, the CS was coated with chitosan as a composite. To sustain its cost-effectiveness, the saturated composite was regenerated with HNO3. Its performance for Cr(III) removal was evaluated and compared to other low-cost adsorbents in previous work. FindingsAt the same initial concentration of 20 mg/L, it was found that the composite had a higher Cr(III) removal (97%) than the chitosan alone under the optimized conditions of 4 g/L of dose, pH 6.5, 200 rpm of agitation speed, and 1 h of reaction time. The isotherm of Cr(III) removal by the adsorbents followed the Langmuir model, while the pseudo-second order reaction was representative to simulate the adsorption data. The Cr(III) removal by the composite was based on attractive columbic forces between the negative charge of the adsorbent's surface and the positive charge of the metal cation. The negative value of ΔG thermodynamic parameter suggests the spontaneous nature of adsorption. The efficiency of machine learning regression (MLR) model was assessed in predicting the experimental data of adsorption. In spite of promising results, treated effluents still could not comply with the required limit of discharge standards of less than 0.5 mg/L mandated by local legislation. Therefore, a subsequent treatment using activated sludge is required. Overall, this work reveals a contribution of unused resources from the coconut and shrimp industries in the form of composite for protecting the aquatic environment.

Efficient and sensitive determination of storage time-temperature marker 5-hydroxy methyl furfural in bee honey based on Fluorescence quenching of human serum albumin

5-hydroxymethyl furfural (HMF) exhibits mutagenic and DNA strand-breaking activity. It is a useful tool to evaluate the effect of heat and time on foodstuffs processing. The fluorescence interaction of HMF with HSA has not been explored to date. Therefore, this work reports the interaction mechanism of HMF with HSA via fluorescence spectroscopy analysis in a simulated physiological environment. The experimental tries showed that HMF intensely quenched the native fluorescence of HSA via the dynamic quenching. According to fluorescence quenching calculations, the binding constants Kb are 1.26x10-4, 2.71x10-4 and 3.19x10-4 M-1 at 298, 303 and 308 K respectively, and the number of binding sites n is almost 1. Thermodynamic parameters values expose that both electrostatic and hydrophobic interactions are accountable for the interaction of HSA and HMF. The presented quenching method for the assay of HMF exhibited a good linearity in the range of 0.1 to 6.66 µg/mL with a detecting limit of 0.0184 µg/mL. These values made the developed method appropriate to be used in the estimation of HMF in samples of bee honey after its extraction using SupelcleanTM ENVI™ -18 SPE Tube. Five bee honey samples show a positive response of HMF after exposing these samples for inappropriate storage or extreme heating.

Adsorption of methyl ester sulfonate surfactant on Berea sandstone: Parametric optimization, kinetics, isotherm and thermodynamics studies

Anionic surfactants are utilized as an enhanced oil recovery (EOR) additive in sandstone reservoirs due to their excellent surface-activity and self-assembly behaviour. Considering the toxicity of some of the conventional surfactants and the clamour for sustainability approach for oil and gas operations, this present study focuses on application of anionic bio-based surfactant (methyl ester sulfonate, MES) synthesized from used cooking oil in EOR. Studies on MES adsorption onto sandstone reservoir rock were conducted, and the influence of static conditions on adsorption rate using Taguchi experimental design approach was explored. Adsorption data were analyzed using various isotherm and kinetics models. The obtained findings from optimization studies showed that salinity had a significant effect on the process, followed by temperature and pH. The concentration of surfactant had the least effect on the static adsorption process. At an optimum initial MES concentration of 500 ppm, salinity of 3.0 wt%, pH of 4.0, and temperature of 30 °C, the maximum extent of MES adsorbed by the sandstone was 98.9±0.69%. Langmuir isotherm and pseudo-second-order kinetics models were found to fit well with the adsorption equilibrium and kinetics data, respectively. The obtained values of thermodynamic parameters confirmed that MES adsorption onto sandstone was feasible, spontaneous, and exothermic.

Preparation and characterization of CS/PAT/ MWCNT@MgAl-LDHs nanocomposite for Cd2+ removal and 4-nitrophenol reduction.

The present study evaluated the performance of multiwalled carbon nanotube (MWCNT)@MgAl-layered double hydroxide (LDH) nanoparticles loaded on poly-2 aminothiazole (PAT)/chitosan (CS) matrix (CPML) to remove Cd2+ ions from aqueous solution. The removal efficiency of modified CS/PAT with MWCNT@MgAl-LDHs was increased significantly compared to pure CS/PAT. The influence of heavy metal ion concentration, pH, temperature, adsorbent dosage, and contact time on the adsorption was examined. The optimum conditions for the adsorption of Cd2+ ions were 25 0C with the adsorbent dosage of 0.06g and initial concentration for adsorption of the Cd2+ 100mg/L at pH = 8. The maximum adsorption capacity was measured to be 1106.19mg/g. The values of thermodynamic parameters namely Gibbs free energy (ΔG°), entropy change (ΔS°), and enthalpy change (ΔH°) indicated the feasibility, spontaneity and the endothermic nature of the adsorption process, respectively. The pseudo-second-order kinetics and the Langmuir model were selected as the best models for the adsorption process. Also, CPML nanocomposite (NC) was successfully tested for p-nitrophenol (p-NP) reduction in the presence of NaBH4. The reaction was nearly completed in 6min. The fabricated CPML-NC could be reused for three consecutive cycles.

Investigating the binding of caffeic acid to human hemoglobin using multispectroscopic and molecular docking approaches

Caffeic acid (CA) is a hydroxycinnamic acid derivative that possess a wide variety of biological properties and is non-toxic to humans. The binding mechanism of CA with human hemoglobin (HHb) was studied for the first time using multispectroscopic and molecular docking methods. The UV–visible absorption spectra showed that CA interacts with HHb through the formation of ground state complex. The fluorescence studies revealed that CA quenches HHb fluorescence by the static mechanism and confirmed the presence of a single CA binding site on the HHb molecule. The negative values of thermodynamics parameters (ΔH,ΔSand ΔG) showed that the binding of CA to HHb is a spontaneous and exothermic process. Hydrogen bonds and van der Waal interactions are the major intermolecular forces that stabilize the HHb-CA complex. Synchronous fluorescence experiments showed that binding of CA altered the microenvironment around tryptophan residues of HHb. Fluorescence resonance energy transfer studies indicated a high propensity of energy transfer from tryptophan residues of HHb to CA. Circular dichroism spectra and catalytic esterase activity confirmed that only minor changes occur in the secondary structure of HHb in the presence of CA. Molecular docking study identified the HHb amino acid residues involved in binding to CA. Analysis of the binding mode of CA with HHb represents an important step in elucidating the molecular mechanism of the protection of HHb from oxidative damage. This will help in understanding the potential role of CA and related antioxidants as therapeutic agents in various blood-related diseases.

Removal of anthracene from vehicle-wash wastewater through adsorption using eucalyptus wood waste-derived biochar

The removal of anthracene from vehicle-wash wastewater (VWW) was investigated using adsorption employing biochar (EWB) generated from eucalyptus wood waste. The EWB was characterized using analytical techniques such as surface area analysis (SAA), scanning electron microscopy (SEM), and fourier transform infrared (FT-IR). The study determined that the most effective conditions to achieve maximum anthracene adsorption (98.40%) were as follows: an initial concentration of 40 ppm, a contact time of 60 min, a pH level of 5, a temperature of 50 °C, and an adsorbent dose of 0.4 g. Isotherms and kinetic models were utilized to evaluate the adsorptive capacity of anthracene. The kinetic analysis results indicate that the anthracene adsorption process onto the EWB is controlled by a pseudo 2nd order kinetic model. The experiment's findings showed that the Langmuir isotherm model provided the most accurate fit to the data. Also, error function analysis was performed. The exothermic and spontaneous nature of the adsorption process is evident based on the values of thermodynamic parameters, including enthalpy (ΔH°), Gibbs free energy (ΔG°), and entropy (ΔS°). The outcomes were also contrasted with the capabilities of a few commercial adsorbents in real-world applications. According to this investigation, the novel EWB exhibits a significant potential, which exceeds 95%, for the extraction and recovery of anthracene from industrial wastewater.

Synthesis of SBA-16 mesoporous silica from rice husk ash for removal of Rhodamine B cationic dye: Effect of hydrothermal treatment time

Recently, the use of silica-containing wastes has gained popularity as an excellent pathway to prepare mesoporous silica materials for applications of adsorption, catalysis and energy. Hence, this report aimed to prepare SBA-16 mesoporous silica samples derived from rice husk ash under varying times during hydrothermal treatment (viz., 24 and 48 h) and named as SBA-16–24 h and SBA-16–48 h. FE-SEM, TEM, XRD, FTIR, Raman and N2 gas adsorption at − 196°C tools were performed to explore the formation of SBA-16. Rhodamine B (RhB) dye uptake from aqueous solutions by both samples was determined by equilibrium isotherms and kinetics. Effects such as pH, dye initial concentration, temperature and contact time were investigated. Results revealed the successful preparation of SBA-16 with an amorphous, ordered mesoporous structure and a higher total surface area of 461 m2/g for SBA-16–48 h obtained during a longer time of hydrothermal treatment. Increasing the time of hydrothermal treatment to 48 h decreased the average particle sizes of SBA from 50–40 nm to 20–10 nm with enhancing the total surface area, mesopore volume and amount of Si-O-Si groups. Equilibrium adsorption isotherms were fitted better by the Langmuir model than the Freundlich Temkin and Dubinin-Radushkevich models. The maximum adsorption capacity calculated from Langmuir model showed that SBA-16–48 h featuring the larger capacity of about 166.7 mg/g at pH 6. Pseudo-second order kinetic is found to be more suitable to describe the adsorption. Negative values of ΔH0 and ΔS0 thermodynamic parameters affirmed that the adsorption of RhB dye is an exothermic and spontaneous process over prepared mesoporous silica. Conclusively, the investigated SBA-16–48 h is a promising adsorbent for effective removal of basic dyes from their aqueous stream.

Spectroscopy and molecular simulation on the interaction of Nano-Kaempferol prepared by oil-in-water with two carrier proteins: An investigation of protein–protein interaction

In this work, the interaction of human serum albumin (HSA) and human holo-transferrin (HTF) with the prepared Nano-Kaempferol (Nano-KMP) through oil-in-water procedure was investigated in the form of binary and ternary systems by the utilization of different spectroscopy techniques along with molecular simulation and cancer cell experiments. According to fluorescence spectroscopy outcomes, Nano-KMP is capable of quenching both proteins as binary systems by a static mechanism, while in the form of (HSA-HTF) Nano-KMP as the ternary system, an unlinear Stern–Volmer plot was elucidated with the occurrence of both dynamic and static fluorescence quenching mechanisms in the binding interaction. In addition, the two acquired Ksv values in the ternary system signified the existence of two sets of binding sites with two different interaction behaviors. The binding constant values of HSA-Nano KMP, HTF-Nano-KMP, and (HSA-HTF) Nano-KMP complexes formation were (2.54 ± 0.03) × 104, (2.15 ± 0.02) × 104 and (1.43 ± 0.04) × 104M−1at the first set of binding sites and (4.68 ± 0.05) × 104 M−1 at the second set of binding sites, respectively. The data of thermodynamic parameters confirmed the major roles of hydrogen binding and van der Waals forces in the formation of HSA-Nano KMP and HTF-Nano KMP complexes. The thermodynamic parameter values of (HSA-HTF) Nano KMP revealed the dominance of hydrogen binding and van der Waals forces in the first set of binding sites and hydrophobic forces for the second set of binding sites. Resonance light scattering (RLS) analysis displayed the existence of a different interaction behavior for HSA-HTF complex in the presence of Nano-KMP as the ternary system. Moreover, circular dichroism (CD) technique affirmed the conformational changes of the secondary structure of proteins as binary and ternary systems. Molecular docking and molecular dynamics simulations (for 100 ns) were performed to investigate the mechanism of KMP binding to HSA, HTF, and HSA-HTF. Next to observing a concentration and time-dependent cytotoxicity, the down regulation of PI3K/AkT/mTOR pathway resulted in cell cycle arrest in SW480 cells.

Kinetics and thermodynamic parameters of palm empty fruit bunch pyrolysis promoted by calcium-rich wastes from coastal-marine residue

Kinetics and thermodynamics of palm empty fruit bunch (PEFB) pyrolysis have been determined in the presence of catalyst from clam shell (Anadara sp.) (CS) using thermogravimetric analysis. PEFB pyrolysis occurred in three stages (moisture and volatile removal, cellulose and hemicellulose, and lignin decomposition), with maximum degradation occurring at 200–400 °C. Activation energy calculated using the iso-conversional method varied from 89.80 to 169.63 kJ/mol for Friedman, 66.25–119.79 kJ/mol for FWO, 53.33–96.44 kJ/mol for KAS, and 50.90–92.04 kJ/mol for Starink. Pre-exponential factor values ranged from 104–1017 and 104–1014 s−1 for non-catalytic and catalytic pyrolysis. The thermodynamic parameters values varied from 47.28 to 99.44 kJ/mol for enthalpy, from 98.23 to 151.62 kJ/mol for Gibbs free energy, and from −0.0858 to −0.0808 kJ/mol for entropy. The reaction mechanism is dominantly second-order and complex. The analysis revealed that PEFB and CaO catalyst from CS are efficient biomass and effective catalyst for bioenergy production.

Treatment methodology for sludge and scale TENORM waste from petroleum industry in Egypt

In this present laboratory work, experiments have been steered to decrease the activity concentration of 226Ra in sludge and scale (TENORM) which Technically Enhanced Naturally Occurring Radioactive Materials waste samples deposited in oilfield tubes and tools, sludge and scale, Egypt, respectively. The influence of the leaching parameters on the radium dissolution mechanism using nonionic surfactant tween 20 as a leaching agent has been determined. The greatest leaching percent of radium isotopes approximated 58.31 % of the total radium percentage in bulk sludge TENORM waste sample (size < 2.5 mm) using tween 20 as surfactant solutions through three successive cycles at the optimum conditions. The greatest leaching percent of radium isotopes was 77.98 and 86.12 % of the total radium percentage in scale TENORM waste samples from two different places, the first place is the western desert area and the second place is Ras Shukeir area, respectively, (size < 1 mm) using tween 20 solutions through four successive cycles at the optimum conditions. The kinetic calculations indicated that the leaching procedure can be explained by the Shrinking Core Model with activation energy equivalent to 18.18 kJ/mol. The low value of activation energy illustrated that the diffusion process controls the sludge TENORM waste sample leaching rate. The estimated values of thermodynamics parameters (ΔG°, ΔH°, ΔS°) were appointed in this study and showed the dissolution of radium is a non-spontaneous response and temperature dependent.

CO2 Physisorption over an Industrial Molecular Sieve Zeolite: An Experimental and Theoretical Approach.

The present work studies the adsorption of CO2 using a zeolitic industrial molecular sieve (IMS) with a high surface area. The effect of the CO2 feed concentration and the adsorption temperature in conjunction with multiple adsorption-desorption cycles was experimentally investigated. To assess the validity of the experimental results, theoretical calculations based on well-established equations were employed and the values of equilibrium, kinetic, and thermodynamic parameters are presented. Three additional column kinetic models were applied to the data obtained experimentally, in order to predict the breakthrough curves and thus facilitate process design. Results showed a negative correlation between temperature and adsorption capacity, indicating that physical adsorption takes place. Theoretical calculations revealed that the Langmuir isotherm, the Bangham kinetic model (i.e., pore diffusion is the rate-determining step), and the Thomas and Yoon-Nelson models were suitable to describe the CO2 adsorption process by the IMS. The IMS adsorbent material maintained its high CO2 adsorption capacity (>200 mg g-1) after multiple adsorption-desorption cycles, showing excellent regenerability and requiring only a mild desorption treatment (200 °C for 15 min) for regeneration.

Exergoeconomic analysis of an integrated electric power generation system based on biomass energy and Organic Rankine cycle

ABSTRACT The present study investigates the thermodynamics analysis of a trigeneration system using a gasifier system. An Organic Rankine Cycle (ORC) system is used to heat recovery and consequently, supplying the cooling demand. The first and second laws of thermodynamics are used to energy and exergy analysis of the system. Some thermodynamic parameters which affect the system performance including combustion temperature, gasifier temperature, compressor isentropic efficiency, gas turbine isentropic efficiency, compressor pressure ratio, and ORC pressure are parametrically analysed and their contribution in improving the efficiency and economy of the system is investigated. To the sustainable performance of the combined system, we need an evolutionary algorithm to identify the optimum values of thermodynamic parameters that have an impact on system performance. Hence, the Multi-Objective Particle Swarm Optimization (MOPSO) algorithm is used to find the best values of decision variables. The most striking result to emerge from the optimisation.optimisation is that implementing the MOPSO algorithm improves the exergy efficiency by 5.17% and reduces the total cost of the system by 1.9%.