Normal Stirring Research Articles

Experimental investigation on the promotion of CO2 hydrate formation for cold thermal energy storage – Effect of gas-inducing stirring under different agitation speeds

To promote the formation of CO2 hydrate for cold energy storage, the influence of gas-inducing agitation at varying operating speeds were studied experimentally. A comparison was made with normal stirring (without gas inducing) from the perspectives of deviation from equilibrium condition, subcooling, agglomeration, and hydrate production. The test results revealed that gas-inducing agitation contributed to a closer shift of the hydrate formation profiles towards equilibrium conditions when compared to normal stirring. However, this advantage became less pronounced as the stirring speed increased. Notably, a substantial improvement in subcooling phenomena was observed when transitioning from 250 rpm normal stirring to 500 rpm, decreasing the induction time to 19.3%. Comparing normal stirring, the incorporation of a gas-inducing stirrer further reduced the induction time by 68.6% at 400 rpm. Nevertheless, further increasing agitation speed for both sets did not yield apparent improvement in the subcooling phenomenon. In contrast to normal stirring, gas-inducing agitation effectively prevented hydrate agglomeration at a lower speed and led to increased hydrate production at the same rotation speed. An ascending trend in hydrate production was achieved as agitation accelerated from a low speed to a specific speed, e.g., 400 rpm for gas-inducing stirring and 500 rpm for normal stirring. However, further elevating the stirring speed did not stimulate greater hydrate production. The findings of this study indicated the existence of double-sided effects in using gas-inducing stirring for hydrate promotion and a crucial speed range (e.g., 400∼450 rpm in this study) essential for the efficient implementation of gas-inducing technology. Operating at this prescribed speed range was recommended to improve the energy Return on Investment, maintaining high hydrate production, and enhancing the controllability of cold storage systems. This study provides practical insights for applying gas-inducing technology in gas hydrate reactors, contributing to the development of green cold energy storage.

Phospholipid-derived Au and Au–Cu suspensions as efficient peroxide and borohydride activators for organic molecules degradation: Performance and sustainable catalytic mechanism

In the contemporary context, executing light-oxidant- and reductant-driven reactions in solution-phase processes remains challenging mainly due to the lack of general tools for understanding the reactive potential of nano-functional catalysts. In this study, dual-active nanometals (Au and Cu doped with Au) capped within soy lecithin (SL), were developed and characterized, combining flexibility with the catalytic advantages and stability of liquid-phase catalysts. The as-synthesized SL-Au (LG) and SL-Au-Cu (LGC) catalysts were efficiently degraded rhodamine B (RB, 100%) in the presence of H2O2 under light irradiation (350 W lamp) at wide pH range (3–7) within 4.5 h and p-nitrophenol (p-NP, >90% degradation at pH 7) in the presence of NaBH4 under normal stirring with slower kinetics (∼72 h). RB degradation followed a pseudo-second-order kinetic model with a higher r2, and p-NP degradation followed first-order kinetics. The active sites embedded within the structural order of SL arrangement displayed elevated catalytic activity, which was further enhanced by the movement of intermediate/excited states and charged elements within the metal suspended in the phospholipid (LG and LGC). The self-regulating tunability of the physicochemical characteristics of these catalysts provides a convenient and generalizable platform for the transformation of modern dual-active (redox) catalysts into dynamic homogeneous equivalents.

Vibration-enhanced disposable electroanalytical platform for selective analysis of tryptophan in fruits based on molecular imprinting

Although electrochemical detection based on molecular imprinting polymers (MIP) could dramatically improve the selectivity, the procedure is time-consuming because of the essential incubation step. In addition, current MIP electrochemical detections were not suitable for analysis of microliter-level sample solutions, limiting their applications for real samples. This investigation aims at applying vibration to enhance efficiency of MIP electrochemical detection of 20 μL sample solutions. MIP analysis of Tryptophan (Trp) was used as the model with disposable MIP electrodes prepared by electrochemical polymerization of o-phenylenediamine on carbon ink coated on stainless steel sheets. The MIP electrode was integrated in a 3D-printed analytical device for vibration-enhanced electrochemical detection of Trp. Our results showed that this vibration-enhanced strategy could significantly increase electrochemical responses of Trp at the same incubation time. Such improvement might be attributed to the enhanced mass transfer at the surface of the working electrode brought by vibration. It needs to be emphasized that this strategy is suitable for analysis of sample solutions with the volume of microliters, which is superior to normal stirring in MIP electrochemical detection. Our approach could be successfully utilized for differentiation of Trp in different fruits, opening more opportunities for MIP electrochemical detection of real samples. The enhanced efficiency by vibration could pave foundation for extensive practical MIP detection of sample solutions at the level of microliters.

Insight into the Effect of Sulfonation Techniques on the Adsorption Properties of -SO3H Surface-Functionalized Coal as Adsorbent for Malachite Green Dye: Steric and Energetic Investigation.

Natural coal (N.C) was sulfonated with sulfuric acid by normal stirring (MS.C) and sonication waves (SS.C) to obtain −SO3H functionalized coal as enhanced adsorbents of malachite green dye (MG). The sulfonated products exhibit enhanced surface area (MS.C (27.2 m2/g) and SS.C (45.8 m2/g)) as compared to N.C. SS.C achieved higher acid density (14.2 mmol/g) and sulfur content (13.2 wt. %) as compared to MS.C. The impact of the sulfonation processes on the adsorption of MG was assessed based on the monolayer isotherm model of one energy. The MG Qsat of N.C (121.3 mg/g), MS.C (226.3 mg/g), and SS.C (296.4 mg/g) validate the significant effect of the sulfonation processes by the sonication waves. This is in agreement with the active site densities that reflect the saturation of SS.C by more active sites (180.74 mg/g) than MS.C (120.38 mg/g) and N.C (70.84 mg/g). The MS.C and SS.C can adsorb three MG molecules as compared to two molecules per site of N.C. The Gaussian energy (<8 kJ/mol) and adsorption energy (<40 kJ/mol)) reflects the physisorption of MG involving van der Waals forces, hydrogen bonding, and dipole bonding forces. The thermodynamic functions demonstrate the uptake of MG by exothermic, spontaneous, feasible reactions.

Insight into the sulfonation conditions on the activity of sub-bituminous coal as acidic catalyst during the transesterification of spent corn oil; effect of sonication waves

The impact of the sulfonation conditions on the catalytic activity of coal as an acidic catalyst was assessed by normal stirring (NS.Coal) and sonication waves (SS.Coal) based on the Response Surface methodology. The NS.Coal exhibits acid density and surface area of 8.8 mmol/g and 27.8 m2/g, respectively. This was obtained after 90 min at sulfonation conditions of 150 °C temperature and 95% H2SO4 concentration. In the existence of sonication waves for 60 min (240 W), SS.Coal shows acid density and surface area of 14.2 mmol/g and 45.8 m2/g, respectively. This demonstrates significant efficiency for the sonication-induced sulfonation processes during the synthesis of sulfonated coal as an acidic catalyst. The activities of NS.Coal and SS.Coal acidic catalysts were evaluated during the transesterification of corn oil. The best yield was obtained by NS.Coal (4 wt, %) is 99.3% after 60 min at 60 °C in the presence of 14:1 methanol/oil ratio. The archived yields using SS.Coal at loading values of 2 wt, %, 3 wt, %, and 4 wt, % are 99.6%, 99.84%, and 99.85%, respectively after 20 min. The kinetic properties of reactions were illustrated based on the Pseudo-First order assumption. The thermodynamic studies demonstrate the endothermic properties of the corn oil transesterification reactions. The determined activation energy by NS.Coal and SS.Coal are 26.22 kJ/mol and 17.7 kJ/mol, respectively reflect the possible use of them as effective catalysts at low energy and mild conditions.

Experimental Studies on the Influence of Plasma Treatment of Polyethylene in Carbon Fiber Composites: Mechanical and Morphological Studies

This research focused on enhancement of mechanical properties in carbon fiber (CF)-filler-reinforced linear low-density polyethylene (PE) matrix composites. A hand layup method using an oven was used as the fabrication method. Improvement in adhesion was achieved by oxygen plasma treatment to the PE matrix. CF and PE were initially mixed by normal stirring, ultrasonication and mechanical stirring before being filtered and dried for fabrication. Better tensile results were observed with a plasma-treated polyethylene (PEP)/10 wt.% CF combination, with a maximum tensile strength of 21.5 MPa and improvement in the properties of up to 12.57% compared to non-plasma PE with the same CF addition. The addition of carbon fibers at 13 and 15 wt.% resulted in a reduction in the tensile strength properties to 18.2 MPa and 17.7 MPa, respectively. This reduction in tensile strength was due to agglomeration of CF with plasma- and non-plasma-treated PE. The fabrication condition of 180 °C temperature for 20 min showed better tensile properties than other conditions. The SEM results following tensile testing revealed enhanced CF filler adherence with plasma PE results, as well as fewer surface deformations. A higher flexural strength of 25.87 MPa was observed for the plasma treated PE/7 wt.% CF combination.

Preparation of floating PDMS sponge catalysts embedded with copper oxide(s): A prelude to the study of its application toward the effective rhodamine B degradation by sonochemical method

In this study, copper oxide (s) embedded polydimethylsiloxane (PDMS) sponge catalysts have been prepared and demonstrated as an efficient heterogeneous catalyst for the Fenton-type degradation of rhodamine B (RB) in an aqueous solution, in which RB was selected as a representative pollutant. Each Cu2O, CuO, and a mixture of Cu2O and CuO embedded with the PDMS sponge were synthesized by respective copper oxides onto a sugar template, followed by the addition of PDMS with an elastomer, degassing, curing, removing sugar templates, and drying in a hot air oven. The resulting catalysts were characterized using FTIR, SEM-EDS, and ICP-OES methods. The as-synthesized catalysts were used to degrade RB utilizing normal stirring and sonochemical methods under a diverse range of reaction conditions. The sonochemical method effectively removed RB (> 98% of 125 mg L–1) from the aqueous solution. Moreover, RB degradation follows relatively faster kinetics (3–9 h) with 750 µL volume of H2O2, and degradation remains consistent with different optimized pH conditions (4–7). This degradation process followed a first order kinetic model with higher r2 values. Experimental results suggest that RB degradation is linked to the interplay among all reagents and coincides with previously reported degradation mechanisms. This sonochemical degradation process followed a first-order kinetic model and the materials were reusable for more than 10 cycles. The facile synthesis, high catalytic performance, reusability, durability, and easy recoverability of the as-prepared catalyst are promising for environmental catalytic pollutant degradation applications in the treatment of organic pollutants at diverse operating conditions.

Dye Adsorption on UiO-66: the Importance of Electrostatic Attraction Mechanism

Adsorption is known as the best technique to remove dyes from waste water, and the choice of adsorbent is the most important factor. In this regard, some commercial porous materials have been applied for a long time as popular adsorbents for dye adsorption. However, the search for new classes of porous materials is still attractive to researchers. Recently, metal-organic frameworks are seen to be promising candidates as adsorbents for dyes due to their large surface area, ordering, and flexible structure. There are some possible mechanisms for the dye adsorption in water performed on metal-organic frameworks, including the electrostatic interaction forming attractive charge of dye molecules and adsorbents, π–π stacking of organic rings from dye and metal-organic frameworks, hydrogen bonding between the dye and hydroxyl group of the metal-organic frameworks, hydrophobic interaction, acid-base interaction and effect of framework structure. Among them, the electrostatic attraction mechanism plays an important role in dye adsorption on MOFs, highlighting differences as compared to traditional adsorbents in this field. This work is the first detailed investigation into the effect of electrostatic attraction mechanism in dye adsorption on UiO-66 and their modifications. Two samples of Co/UiO-66 and H+/UiO-66 were prepared under normal stirring and heating conditions to increase the positive charge of the surface. The characterization using powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FTIR indicated the existence of proton on UiO-66, while Raman spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS) confirmed the successful addition of cobalt into the UiO-66 structure at the amount of about 0.6 wt %. Results obtained for methyl orange (MO) adsorption on the surface have shown enhanced adsorption capacity for both Co-UiO-66 and H+/UiO-66 as compared to parent UiO-66. Moreover, the experiments with highly selective removal of anionic dye as compared to cationic dye were performed and explained in detail for mixed dye solutions of MO with methylene blue (MB), indicating the important role of electrostatic attraction mechanism. Notably, it is shown that the addition of Co to UiO-66 results in a higher effect of electrostatic interaction than that of H+.

Insight into the catalytic conversion of palm oil into biodiesel using Na+/K+ trapped muscovite/phillipsite composite as a novel catalyst: Effect of ultrasonic irradiation and mechanism

A novel composite of muscovite/synthetic zeolite (phillipsite) (Mu/Pz) was synthesized in an open system by the alkaline modification at 150 °C under stirring of speed 600 rpm for 22 h. The composite was characterized as a novel, low cost and effective basic catalyst in the transesterification conversion of palm oil into biodiesel. The catalytic properties of Mu/PZ were studied based on several controlling factors by normal stirring and ultrasonic irradiation as mixing techniques. The maximum biodiesel yield obtained by normal stirring is 94% and was accomplished after adjusting the controlling factors at 180 min as conversion interval, 20:1 as the incorporated methanol-to-oil molar ratio, 100 °C as reaction temperature, 5 wt, % as a Mu/Pz loading and 1300 rpm as a stirring speed. The influence of ultrasonic irradiation was addressed within a range from power 20% to power 60% and the best results were achieved using ultrasonic power of 60%. At the same conducting conditions of temperature, Mu/Pz loading, and the incorporated methanol-to-oil ratio, the biodiesel yield attained 97.8% after 90 min by using ultrasonic irradiation as a mixing method at 60% power. The stability study of Mu/Pz catalyst revealed high reusability properties for five cycles using three regeneration solvents of distilled water, methanol and acetone with clear preferences for using the organic solvents. The specifications of the obtained biodiesel samples by both methods match the biodiesel requirements of the STM-D-6571 as well as the EN-14214 international standards.

Synthesis of Na+ trapped bentonite/zeolite-P composite as a novel catalyst for effective production of biodiesel from palm oil; Effect of ultrasonic irradiation and mechanism

Bentonite/zeolite-P composite (B/ZP) was synthesized by simple alkaline hydrothermal treatment at 150 °C for 4 h and characterized by different analytical techniques. The composite was introduced as a low-cost catalyst of enhanced physiochemical properties and catalytic activity in the transesterification of palm oil into biodiesel. The catalytic activity of B/ZP catalyst was inspected by normal stirring mixing and under ultrasonic irradiation of different powers (20–60%). The best biodiesel yield by normal stirring (96.2%) was achieved at operating conditions of 210 min as conversion time, 20:1 as a methanol-to-oil molar ratio, 5 wt% as a catalyst loading, 90 °C as temperature and 900 rpm as stirring speed. The conversion reaction under the ultrasonic irradiation (power 60%) gives biodiesel yield of 98.8% after 120 min as reaction time using 5 wt% as catalyst loading, 20:1 as a methanol-to-oil ratio, and 90 °C as temperature. The ultrasonic irradiation is of positive impacts in reducing the conversion time interval, reaction temperature, catalyst loading, and methanol-to-oil molar ratio with biodiesel yield similar to that obtained by normal stirring at its best conditions. The catalyst is of higher activities than several homogenous and heterogeneous catalysts and can be reused several times with high catalytic activity especially using an organic solvent either by normal stirring or under the ultrasonic irradiation. The physicochemical specification of the obtained biodiesel by both methods matches the requirements of STM D-6571 and EN 14214 international standards.

Strong tribocatalytic dye decomposition through utilizing triboelectric energy of barium strontium titanate nanoparticles

In the suspensions with the Ba0.75Sr0.25TiO3 (BST) nanoparticles with an average size ~20 nm for triboelectric energy harvesting, dye decompositions were found to occur readily in the course of a normal stirring in dark at room temperature. More importantly, the decomposition efficiency can be greatly improved through some simple modifications in stirring rods and as high as 99.0% Rhodamine B can be decomposed in 3 h under a mild stirring of 300 rpm. Some well-designed experiments have been conducted, which show that the observed dye decompositions are directly related to the friction between BST nanoparticles and stirring rods in magnetic stirring. It is proposed that with the mechanical energy absorbed from friction, the BST nanoparticles have exerted a novel tribocatalytic effect for dye decompositions, which is confirmed by the detection of intermediate products of •OH and •O2− in stirring. These results clearly demonstrate that nanostructured oxides have the capability to harvest mechanical energy from ambient environment through friction for dye decomposition, which represents an important application for harvesting mechanical friction energy.

Microstructure, texture evolution and mechanical properties of pure Ti by friction stir processing with slow rotation speed

The microstructure and texture characteristics of commercial pure Ti after friction stir processing (FSP) with a slow rotation speed were studied. The shoulder friction zone (SFZ) which did not exist in the FSPed pure Ti with normal rotation speed (> 250 rpm) was observed in the sample treated with a slow rotation speed of 180 rpm. The texture of SFZ in the pure Ti was affected by shear stress from the shoulder of stir tool and the c-axes of the grains in this zone were nearly parallel to the processing direction. While crystallographic texture in the normal stir zone (SZ) were nearly perpendicular to the processing direction. The maximum depth of SFZ in the sample with 180 rpm was 1.2 mm, which decreased with the increased rotation speed until it disappeared. The grains in the SZ of specimen following FSP at a slow rotation speed were fine and homogeneous. The microhardness increased from 150.2 HV to 191.6 HV after FSP at 180 rpm. The microhardness trends were related to grain sizes, work hardening and texture evolution. The slow rotation speed processed alloy boosted the yield strength by 71.7% after the FSP.

MITOCHONDRIAL DISEASES (Posters): P.189A novel case of MSTO1 gene related congenital muscular dystrophy with cerebellar involvement

Recessive mutations in the MSTO1 gene, encoding for a mitochondrial distribution and morphology regulator, have been recently described in 4 families with multisystem involvement, mostly characterized by myopathy or dystrophy, cerebellar ataxia, pigmentary retinopathy and raised CK. Here we report a patient with recessive MSTO1 gene related muscular dystrophy and ataxia. The patient, born to non-consanguineous parents, presented at age 2 years with global developmental delay. At age 15 years he was ambulant and showed axial, upper and lower limb weakness, pronounced proximally, scoliosis, ankle contractures and ataxia. There was no cardiac or respiratory involvement. EMG was normal. Brain MRI at 6 years showed cerebellar atrophy and mild under-opercularisation of the left Sylvian fissure; when repeated at 9 years, there was mild progression of cerebellar atrophy and additional supratentorial sulcal prominence suggestive of volume loss. Muscle MRI showed generalized increase in T1 signal in the lower limb with normal STIR sequences. CK was raised (800-1614 IU/L). Muscle biopsy showed fibre size variability, increased internal nuclei, fatty endomysial infiltration, few regenerating fibres, type 1 predominance and some minicores. Minor changes of uncertain significance on laminin-α and a-dystroglycan staining were observed. Respiratory chain enzyme studies were normal. Whole-exome sequencing revealed 2 missense MSTO1 variants. The first variant (c.766C>T p.(Arg256Trp)), affecting a conserved residue in the tubulin domain of the protein, is reported in the gnomAD dataset with an allelic frequency of 0.00003, while the second (c.1435C>T p. (Pro479Ser)) is novel. In silico tools predict both variants as damaging. Phasing of the variants is in progress. This case confirms a consistent phenotype associated with recessive MSTO1 gene mutations and suggests that progressive cerebellar atrophy can be a feature of the condition.

Encapsulation of nano-catalysts in permeable silicone elastomers

• Encapsulation of multiple types of nano-catalysts. • Encapsulated catalysts are unbreakable in normal stirring condition. • Low metal leaching.

Shape-selective catalysis and surface enhanced Raman scattering studies using Ag nanocubes, nanospheres and aggregated anisotropic nanostructures.

Three morphologies of silver nanoparticles (Ag NPs) such as nanocubes, aggregated anisotropic Ag NPs, and nanospheres were prepared using polystyrene sulfonate (PSS) and citrate as stabilizing agents utilizing a simple wet-chemical and microwave heating route respectively. Ag nanocubes were prepared within one min through microwave heating whereas anisotropic Ag NPs and spherical Ag NPs via 5 and 30min of normal stirring at room temperature (RT) respectively. The shape effect of three different morphologies of Ag NPs were examined in catalysis reaction and in surface enhanced Raman scattering (SERS) studies. For catalysis experiments, reduction of various nitroaromatics was done taking excess NaBH4 in presence of those morphologically different Ag NPs as catalyst and the corresponding catalytic activity is ordered as: Ag nanospheres>aggregated anisotropic Ag NPs>Ag nanocubes. The highest catalytic rate of ∼1.34×10-1min-1 was observed with citrate capped Ag nanospheres. SERS study was done taking methylene blue (MB) as the Raman probe where a highest enhancement factor (EF) of ∼1.05×107 was observed with Ag nanospheres and the order of EF values is as follows: Ag nanospheres>Ag nanocubes>aggregated anisotropic Ag NPs. The highest catalytic and SERS activity of citrate stabilized spherical Ag NPs are attributed due to the fast electron transfer in catalysis and creation of more number of surface active 'hot spots' in SERS studies. In future, the overall process we highlighted here might found potential application for the preparation of other varieties of nanomaterials applicable to catalysis reaction and in SERS-based trace analysis of various biologically important molecules and fine chemicals.

Effect of Particle Size on Mechanical Properties of Al-RMp Metal Matrix Composites

Particle reinforced aluminum matrix composites (AMC) have invoked a potent interest in recent times for applications in aerospace industries. Al- MMCs have improved mechanical, tribological, strength to weight ratio when compare to monolithic metals and alloys. Red mud (RMp), a residue of a Bayer process was selected as reinforcement with three different grain sizes of 90,120,180 microns and wrought aluminum alloy 8011 as a matrix material. Normal stir casting route is adopted to cast the composites by varying the wt.% of the RMp from to 4% to 20% in increment of 4%. Prepared composites are then tested for mechanical properties as per the ASTM standards. From the obtained results it is observed that 24.45% increase in tensile strength in Al-14wt% RMp90 composition and good hardness and compressive strength in Al-20wt% RMp180 composition is obtained.

Ultrasound-Assisted Aqueous Enzymatic Extraction of Oil from Pomegranate Seeds

Pomegranate seed oil presents nutraceutical properties. Industrial processes for extraction of edible oils from seeds generally involve a solvent extraction step. Safety considerations on the use of organic solvents prompted attempts to develop aqueous extraction. However, aqueous extraction processes are usually characterized by low oil yields. The objective of this work was to overcome these low yields by using enzymes. The pomegranate seeds were treated with two enzymes—cellulase and Peclyve V. The extraction temperature, the time, the enzyme concentration, and the water/seeds ratio were varied between 35 and 55 °C, 2 and 8 h, 2 and 4 % w/w, and 2/1 and 6/1 mL/g, respectively. The optimum yield accomplished (15.33 g oil/100 g dry seeds at 2 h or 81 % oil recovery) was comparable to the yields obtained by other extraction methods, such as normal stirring, cold pressing, superheated fluid extraction, indirect ultrasound-assisted extraction and supercritical extraction, (4.29–25.11 g oil/100 g seeds) at similar or longer extraction times (10 min–72 h). In addition, this work studies the enhancement of aqueous enzymatic extraction of pomegranate seed oil by ultrasound probe. It was found that only 10 min in water are needed to recover oil with a yield of 18.15 g oil/100 g dry seeds, a value similar to or higher than those of the conventional procedures. Thus, the use of ultrasounds increased the yield of enzymatic extraction by 18.4 % and reduced the extraction time by 91.7 %.

Chiral Ni-Schiff Base Complexes inside Zeolite-Y and Their Application in Asymmetric Henry Reaction: Effect of Initial Activation with Microwave Irradiation

Chiral Ni(II)-Schiff base complexes synthesized inside the cavity of zeolite-Y were used as heterogeneous chiral catalyst for asymmetric Henry reaction. Synthesized catalysts were characterized using various spectrochemical and physicochemical techniques. Solid state NMR analysis has been used to confirm the internal location of the metal complexes. To the best of our knowledge MAS NMR has not been used to characterize chiral diamagnetic Ni2+-Schiff base complex inside zeolite-Y. The catalytic activities of the materials were dependent on temperature, solvent, and amount of catalyst. High catalytic transformation of aldehydes with nitromethane to nitro-aldol product (92% yield and 83% ee, S-isomer) was achieved at −10 °C. Initial activation of the reaction with microwave irradiation for 15 min leads to a substantial decrease in the reaction time in comparison to normal stirring. Heterogeneous catalysts were found to be advantageous over the homogeneous counterparts in terms of recyclability of the catalys...

Safety enhancement by transposition of the nitration of toluene from semi-batch reactor to continuous intensified heat exchanger reactor

The behavior of a continuous intensified heat exchanger (HEX) reactor in case of process failure is analyzed and compared to the behavior of a semi-continuous reactor. The nitration of toluene is considered as test reaction to identify the main failure scenarios that can lead to thermal runaway in both processes using the HAZOP method. No flow rate of process fluid and utility fluid in the continuous process. No stirring during feeding of the reactor followed by normal stirring for the semi-continuous reactor. These scenarios are simulated for both processes and the temperature profiles are observed. This study shows that the temperature is better controlled in the continuous process because of the intrinsic characteristics of the HEX reactor. In fact, this device has a low reactive volume relative to the mass of the reactor, allowing a good dissipation of the heat produced by the reaction, even in case of failure. This characteristic of the intensified reactor is confirmed by an experimental work.

Sunlight and microwave induced preparation of activated carbons and their removal of lead(II) and cadmium(II) from industrial effluent

This study briefs about the conditions for preparation of activated carbons from pectin, citrulline, and cellulose rich Annona squamosa shell (custard apple shell) using phosphoric acid (H3PO4). The influence of time, temperature, and impregnation ratio on the yield were studied on the preparation of activated carbon by conventional i.e. normal stirring method (CAC), microwave assisted (MAC), and sunlight assisted synthesis (SAC). Also, the characteristics of all the three carbons were determined and found to have high surface areas using Brunauer–Emmett–Teller analysis. The prepared activated carbons were optimized for lead (Pb2+) and cadmium (Cd2+) uptake from aqueous solution and further the same was used to treat industrial effluent. The Langmuir isotherm was used to correlate equilibrium data of the adsorption of Pb2+ and Cd2+ by the prepared activated carbons.