Reactor Temperature Research Articles

Innovative magnetic catalyst facilitates biodiesel production via transesterification of sunflower and waste cooking oils

ABSTRACT The surging global demand for biofuels, precipitated by concerns regarding fossil fuel limitations and their associated environmental consequences has thrust biodiesel into the spotlight as a promising alternative of energy source. In this research endeavor, a novel magnetic catalyst, denoted as K compounds/Fe3O4, was developed by incorporating potassium into the magnetite structure via sol–gel method. This catalyst was applied in the transesterification reaction to convert sunflower and waste cooking oils to biodiesel. It was found that the most effective catalyst for biodiesel production was synthesized by using potassium nitrate at a concentration of 1 M and calcination temperature of 550°C in the catalyst preparation stage. The K compounds/Fe3O4 catalyst was characterized by XRD, XRF, FTIR, SEM, ASAP, and VSM techniques. SEM images demonstrated the porous structure of the catalyst. The GC-mass analysis confirmed the formation of fatty acid methyl esters. The effects of the operating conditions including reactor temperature (55 to 75°C), catalyst dosage (2.5 to 12.5 wt.%), methanol to oil molar ratio (9:1 to 18:1), time (4 to 14 h) were investigated. The best operating conditions were selected inclusive of temperature 65°C, catalyst dosage 5 wt.%, methanol-to-oil ratio 12:1, and time 8 h, and at these operating conditions, biodiesel production efficiencies of 96.28% and 84.05% were obtained for sunflower and waste cooking oils, respectively. The reusability and regeneration of the K compounds/Fe3O4 were studied for five cycles.

Safety assessment of the process Acepolymer, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Acepolymer (EU register number RECYC305), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panel concluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hot fill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Ambiental de Plasticos Recyclapet, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Ambiental de Plasticos Recyclapet (EU register number RECYC304), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panelconcluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hot fill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Poly Recycling, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Poly Recycling (EU register number RECYC307), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panelconcluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Shangrao Bisource Technology, based on the Vacurema Prime technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Shangrao Bisource Technology (EU register number RECYC306), which uses the Vacurema Prime technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are heated in a batch reactor (Step 2) under vacuum and then treated at higher temperature in a continuous reactor (Step 3) under vacuum before being extruded into pellets. Having examined the challenge test provided, the Panel concluded that Steps 2 and 3 are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these steps are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1 μg/kg food. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, soft drinks, juices, tea, milk, oil, alcoholic beverages and other food products, for long-term storage at room temperature or below, with or without hot fill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Optimization of an Industrial Methanol Reactor Using Aspen Plus Simulator and Design Expert

The chemical conversion of carbon dioxide into methanol has the potential to address two major sustainability issues: the economically viable replacement of fossil energy resources and the avoidance of greenhouse gas emissions. However, the chemical stability of carbon dioxide poses a difficult barrier to its conversion, necessitating extreme reaction conditions, resulting in increased energy input and, subsequently, elevated equipment, operation, and environmental costs. This, in turn, could potentially undermine its promising sustainability as a raw material for the chemical and energy industries. This research aims to optimise methanol production from a methanol reactor by using design of experiment (DOE) in Design Expert and Aspen Plus as a reactor simulator. The optimisation process involved eight parameters: five inlet molar flowrates (CO, CO2, H2O, H2, CH3OH) and three reactor conditions (inlet temperature, pressure, and temperature profile). The methanol production in Design Expert was optimised using the Box-Behnken method and a quadratic model. This study used the maximum range for each parameter as the actual industrial data and the minimum range to be 50% below it. The validated Aspen-Plus model was used for methanol production simulation. Response surface methodology (RSM) was used to determine the optimal parameters. This simulation required 120 samples. The optimal parameter values from the RSM were 142.2 kmol/hr of inlet CH3OH, 2250.91 kmol/hr of CO, 1398.3 kmol/hr of CO2, 15.6973 kmol/hr of H20, 19053.7 kmol/hr of H2, 497.883K of reactor inlet temperature, 81.9999 bar of reactor pressure, and 30K for reactor temperature profile with the actual methanol production of 2814.23 kmol/hr. The optimal values were simulated to test the accuracy of the predictive model, and the error was less than 5.2 percent. Overall, the inlet H2 molar flowrate was reduced in optimised conditions, reducing raw material usage and increasing output.

Validation of the fast reactor plant dynamics analysis code Super-COPD using FFTF loss of flow without scram test #13

The Japan Atomic Energy Agency (JAEA) has been developing a plant dynamics analysis code named Super-COPD for design studies and safety analyses of sodium-cooled fast reactors. Since there are a few validation studies of a thermal–hydraulic model in a plant, including a point kinetics model considering reactivity feedback for anticipated transient without scram (ATWS) events classified into the beyond design basis events (BDBEs), further validation studies under BDBE conditions are needed to improve the prediction accuracy of the model. Therefore, JAEA has participated in the international benchmark analysis of loss of flow without scram (LOFWOS) test #13 performed at the Fast Flux Test Facility (FFTF) as one of passive safety demonstration tests hosted by the International Atomic Energy Agency. In the first step, the transient calculation with major reactivity feedback mechanisms and imposing measured power history was conducted with Super-COPD. The results were compared with the measured data. Several challenges were identified about the thermal–hydraulic model in the core and heat transport systems and the reactivity model in the point kinetics model. Consequently, the transient calculation was performed with modified models considering the radial heat transfer, flow redistribution, and interwrapper flow in the core. The time-dependent change and the second peak of the outlet temperature in the specified assembly were predicted accurately because the core thermal–hydraulics was reproduced well. Furthermore, the assembly bowing reactivity model was developed to improve the net reactivity, thereby resulting in a good agreement with the measured data on the reactor power, temperature, and flow rate in the primary loop. Thus, this paper proves the validation of Super-COPD for the LOFWOS event in the BDBE.

Modeling and Parameter Tuning for Continuous Catalytic Reforming of Naphtha in an Industrial Reactor System

A two-dimensional mathematical model was developed to simulate naphtha reforming in a series of three industrial continuous catalytic regeneration (CCR) reactors. Discretization of the resulting partial differential equations (PDEs) in the vertical direction and a coordinate transformation in the radial direction were performed to make the model solvable using Aspen Custom Modeler. A sensitivity-based parameter subset selection method was employed to identify the most influential parameters within the model. Tuning of 8 out of 180 parameters was used to ensure that model predictions match experimental data from one steady-state run. The updated parameter values improved the model fit to the data, reducing the weighted least-squares objective function for parameter estimation by 73%. The proposed model was used to predict reactor temperatures, catalyst coke weight fraction at the exit of the third reactor, and benzene flowrate from the outlet of the third reactor. The simulation results demonstrated a good agreement between the simulated values and the industrial measurements. Finally, the reactor model was utilized to explore the effects of changes in inlet temperatures and inlet level of catalyst deactivation, providing valuable insights for identifying desirable operational conditions that will improve the overall efficiency of the CCR process.

Beyond equilibrium ammonia synthesis in a membrane and heat exchange integrated microreactor: A modeling study

Ammonia (NH3) synthesis is modeled in a micro–structured membrane reactor (MR) comprising reaction, cooling and NH3 separation functions in the same volume. The proposed MR involves permeate and reaction channels segregated by layers of zirconia supported ZnCl2 immobilized molten–salt (IMS) membrane selective to NH3 transport. While H2 + N2 is fed to reaction channels washcoated with an iron–based catalyst, permeate channels host N2 as the sweep gas which also regulates reaction temperature. The in–situ cooled MR is modeled by considering mass, momentum and energy conservation in the fluid phases of the reaction and permeate channels, reaction in the catalyst layer and NH3 transport across the membrane, whose thermal stability limit of 623 K is set as the maximum reactor temperature. Upon N2 sweep dosing equal to 50 × the molar H2 + N2 input at H2/N2 = 3, 613 K, 50 bar and 1.5 × 103 m3 kgcat–1 s−1, MR can deliver ∼47 % N2 conversion which exceeds 40 and 13.5 % of the pertinent thermodynamic barrier and the membraneless case, respectively. Despite the exothermic heat release, co–current partitioning of the streams ensures operability below 623 K. Increasing space velocity and H2/N2 ratio, and decreasing inlet temperature and pressure inhibit reactor performance. Using molar sweep–to–reactive mixture ratios < 50 is penalized by the violation of the specified maximum temperature. Membrane integration can improve NH3 production by ∼3.5 times per unit amount of H2O consumed in its electrocatalytic conversion to H2.

Exploring the characteristics of coke formation on biochar-based catalysts during the biomass pyrolysis

Catalyst deactivation by coke formation is one of the main barriers to the application of biomass catalyst pyrolysis. The coke characteristics of biochar-based catalysts (BZ) were systematically studied at different reaction times and temperatures in a tube furnace reactor with poplar wood chips as the biomass feedstock. The morphology, pore structure, chemical structures and composition of soluble coke of BZ were investigated separately. And the reaction mechanism of coke formation was established. Coke was formed by the continuous dehydrogenation and deoxygenation of small molecule reactants and the aggregation. And at low temperatures, coke tended to be generated on the outer surface, but at high temperatures, coke was preferentially formed in the catalyst pore channels. Phenols and oxygenates were the main substances that promoted the coke formation. The high temperature and long reaction time promoted the conversion of coke formation from aliphatic hydrogenation to aromatization and graphitization. The concept of “coke level” based on hydrogen pool theory can better measure the amount and the degree of graphitization of coke. The greater the Clevel, the higher the graphitization and the more the amount of coke. This study is helpful to understand the coke nature and formation mechanism on biochar-based catalysts, which is beneficial to the application of biochar-based catalysts in the biomass pyrolysis.

Overall Reaction Rate Study of Thermal Methane Cracking in Non-Isothermal Conditions

The thermal cracking of methane (TMC) is a significant reaction occurring above 850°C, which proceeds in two stages: non-isothermally and isothermally. However, most existing studies have focused on obtaining reaction rates under isothermal conditions [1], limiting their applicability to practical industrial reactor conditions. This novel research aims to determine the overall thermal decomposition rate of methane to hydrogen and carbon in adiabatic conditions, covering the range of unstable industrial reactor temperatures (850 to 1200°C). The Coats and Redfern model-fitting method was employed to calculate the reaction rate under non-isothermal conditions, and the resulting models were compared with experimental data. The findings reveal the Contracting Cylinder model as the best-fit mathematical representation with less than ±2.8% error. By extending the kinetic model to non-isothermal conditions, this approach addresses a critical aspect of real-world applications.

Process Integration Approach to the Methanol (MeOH) Production Variability from Syngas and Industrial Waste Gases

Methanol is expected to be a possible solution for reducing global greenhouse gas emissions and minimizing the dependency on fossil fuels. This paper presents a systematic approach of methanol (MeOH) production from industrial waste gases including flue gas (FG) and coke oven gas (COG) that are considered an important threat to the environment. The impact of process parameters, including dimensional parameters (length, diameter, and number of tubes) and operational parameters (reactor temperature, pressure, and thermal fluid temperature) over the MeOH synthesis, are investigated by Aspen Plus. Firstly, the synthesis process is designed and optimized using syngas (SG) as a feed material. Secondly, by replacing the feed material with FG and COG, methanol production variability is investigated and demonstrated for the same optimized process. Afterward, an efficient heat exchange network system is developed for all three different processes using Aspen Energy Analyzer. The optimized dimensional parameters of the MeOH synthesis reactor are determined to be a length of 12 m, a diameter of 0.06 m, and 5000 tubes for achieving a conversion rate of 75%. Meanwhile, the optimized operational parameters are identified as a reactor temperature of 209 °C, reactor pressure of 70 bar, and thermal fluid temperature of 196 °C. Furthermore, the influence of the stoichiometric number (SN) on the process was observed with higher SN values resulting in increased hydrogen (H2) concentration and an improved forward reaction of MeOH synthesis, leading to higher conversion rates. The findings and insights gained from this study can serve further improvements and advancements in MeOH synthesis processes.

Pra Rancangan Pabrik Epiklorohidrin dari Diklorohidrin dan Natrium Hidroksida dengan Kapasitas 50.000 Ton/Tahun

The rapid development of the chemical, automotive and electronic industries has made the demand for epichlorohydrin increase every year. Currently there is no epichlorohydrin factory in Indonesia so that the industry's need for epichlorohydrin is met from imports. Therefore, the establishment of an epichlorohydrin factory has quite positive prospects for reducing these imports. The preparation of epichlorohydrin begins by reacting dichlorohydrin with sodium hydroxide with a mole ratio of 5 : 1 in 2 stirred tank flow reactors (RATB) at a reactor temperature of 80 ℃ and a pressure of 1 atm. This reaction takes place with an optimum conversion of 95.4% and is exothermic so water cooling is used to maintain the operating temperature. The utilities needed consist of 200183.1275 kg/hour of water, 74 m3/hour of compressed air, 2170.3770 kW of electric power supplied from PLN with a backup generator. The required fixed capital is Rp. 396 billion and working capital of Rp. 420 billion. Production costs (manufacturing costs) are Rp. 2 trillion, and general expenses are Rp. 616 billion. Profit before tax is IDR 100 billion and after tax is IDR 65 billion. This factory is classified as low risk with a Return Of Investment (ROI) before tax of 25.28% and 16.43% after tax. Pay Out Time (POT) before tax is 2.83 years and after tax is 3.78 years). Net Present Value (NPV) IDR 47 billion. Break Event Point (BEP) 40.69 % and Shut Down Point (SDP) 33.13 %.

Impacts of river snails rice noodle ingredients addition on the kitchen waste anaerobic digestion performances, microbial communities and metabolic pathways

With the rapid development of the river snails rice noodle industry, the treatment of the wastewater generated in the production of river snails rice noodle has attracted people’s attention. This study investigated the performance of the anaerobic digestion of kitchen waste with river snails rice noodle ingredients, including key enzyme activities, microbial community distribution and metabolic pathways in the anaerobic reactor. The average chemical oxygen demand removal efficiencies were 92.5% and 88.7% when 130 g and 260 g river snails rice noodle ingredients were added in the anaerobic reactor, respectively. Acetate kinase activity of the sludge decreased during anaerobic digestion, but increased at 35 °C on days 55. The river snails rice noodle ingredients inhibited the growth of Proteobacteria and the expression of methane metabolism. An increase in temperature promoted the presence of Bacteroidetes and Methanothrix (increased by 3.95% and 2.64% respectively). The later stage of experiment demonstrated an increase in the glycolysis rate-limiting enzymes ATP-dependent phosphofructokinase and pyruvate kinase. It was illustrated that the addition of river snails rice noodle ingredients inhibited the processing capacity of the anaerobic digestion reactor, and the increase of operating temperature of anaerobic reactor alleviated the inhibition of higher content river snails rice noodle ingredients on anaerobic digestion process. It was provided valuable basic information for the future study of treatment of river snails rice noodle wastewater.

Reaction Temperature Manipulation as a Process Intensification Approach for CO2 Absorption

Reactor temperature manipulation to increase product yields of chemical reactions is a known technique used in many industrial processes. In the case of exothermic chemical reactions, the well-known Le Chatelier’s principle predicts that a decrease in temperature will displace the chemical reaction toward the formation of products by increasing the value of the equilibrium constant. The reverse is true for endothermic reactions. Reactor temperature manipulation in an industrial system, however, affects the values of many variables, including physical properties, transport parameters, reaction kinetic parameters, etc. In the case of reactive absorption, some variables change with increasing temperatures due to solute absorption, while others change in such a way that the solute absorption rate decreases. For example, temperature drop increases product formation for exothermic reactions but reduces the value of transport parameters, leading to decreasing interfacial concentrations and absorption rates. Therefore, temperature manipulation strategies must be designed carefully to achieve the process goals. In this work, we theoretically study the use of temperature as a tool to increase CO2 absorption by solvents in a semi-batch reactor. A computer code has been developed and validated using reported experimental data. Calculated results demonstrate an increase in absorbed CO2 of more than 28% with respect to the highest temperature used. Despite high agitation and high gas flow rate, the system is mass transfer controlled at short times, becoming kinetically controlled as time increases. An operating strategy to decrease cooling energy costs is also proposed. This study reveals that reactor temperature manipulation can be an effective process to improve CO2 absorption by solvents in two-phase semi-batch reactors.

Integrated hydropyrolysis and vapor-phase hydrodeoxygenation process with Pd/Al2O3 for production of advanced oxygen-containing biofuels from cellulosic wastes

This study focuses on developing advanced oxygen-containing biofuels with high furan, cyclic ketone, and ethanol content from holocellulose and cellulosic wastes. To achieve this, we employed an integrated process that combined hydropyrolysis and vapor-phase hydrodeoxygenation using Pd/Al2O3 as a catalyst. In the first stage, the non-catalytic hydropyrolysis of hemicellulose resulted in furfural and acetic acid fractions that were effectively converted into furans, cyclic ketones, and ethanol in the second-stage reactor over Pd/Al2O3 under 0.3 MPa H2. We found that a hydropyrolysis temperature of 440 °C in the first stage reactor resulted in the highest yield of oxygen-containing biofuels (171.1 mg/g) with 89.2% hemicellulose conversion. However, increasing the hydrodeoxygenation temperature in the second stage reactor reduced the yield of oxygen-containing biofuels, and at 400 °C, excess deoxygenation led to hydrocarbon production. The Pd/Al2O3 catalyst demonstrated high stability during the vapor-phase hydrodeoxygenation of primary furfural and acetic acid intermediates, with only 2.1% coke formation after three reaction cycles. This scalable process enables the conversion of various cellulosic wastes into advanced oxygen-containing biofuels, with considerable total yields. Our findings suggest that this integrated process holds great promise for converting biomass waste into advanced oxygen-containing biofuels.

Thermodynamic and environmental analysis of self-thermal antibiotic residues supercritical water gasification system for hydrogen and power production

Efficient treatment of antibiotic residue, containing a range of persistent organic compounds, is essential to ensure the protection of both the environment and human health. Supercritical water gasification technology could achieve the clean and efficient energy conversion of antibiotic residues. In this paper, a self-thermal supercritical water gasification system for antibiotic residues is developed to convert antibiotic residues to high-purity H2 and electrical power. The system analysis results demonstrate that increasing the antibiotic residue slurry concentration, elevating the gasification reactor temperature, and optimizing the ratio of water-to-dry antibiotic residues effectively enhance system efficiency and H2 yield within specific ranges. The H2 yield and net electrical power at optimal operating conditions are 634.52 kg/h and 2.3 MW with 10 t/h dry antibiotic residue feeding. Meanwhile, the energy efficiency, exergy efficiency, and cold gas efficiency of the system are 61.32%, 63.05%, and 53.96%, respectively. The life cycle assessment analysis shows that the global warming potential of the system is 20.77 kg CO2-eq/kg H2 with the above operating conditions. Taking into account the emission reduction impact of the system on thermal power generation, the inclusion of CO2 capture and storage units can potentially lead to a negative global warming potential for the system.

Application of PAT in pharmaceutical manufacturing: model‐based control of particle size distribution in anti‐solvent aided crystallization

AbstractBACKGROUNDCrystallization plays a key role in determining the physiochemical properties of an active pharmaceutical solid, which are crucial for drug product performance as well as processibility in downstream operations. Precise control of crystallization parameters is hence necessary to maintain drug efficacy and consistency during active pharmaceutical ingredient (API) manufacturing. In our earlier work on crystallization of dexlansoprazole API, an empirical model was established with reactor temperature and addition time of anti‐solvent identified as critical process parameters (CPPs) and particle size distribution (PSD) as critical quality attribute (CQA). In this study we demonstrate model‐based control of particle size when disruptive incidences occur under a process analytical technology framework.RESULTSExperiments highlighted the deviation in PSD (CQA) on performing a planned disruption event in the form of temporary shutting down the anti‐solvent feeding dosing pump. Once the deviation had occurred due to process disruption, the desired set‐point of particle size was achieved by making the desired changes estimated from model equations for individual CPPs. The change was signaled to the temperature control system or the dosing pump, which then set the revised process conditions in real time during crystallization.CONCLUSIONThe study utilizes an empirical model to achieve the desired particle size by making suitable real‐time changes in CPP in view of process disruption. The case study aligns with the paradigm of quality by design, which expects manufacturers to understand their processes and their products and have in‐built controls to ensure that the resulting product consistently meets the approved specifications. © 2023 Society of Chemical Industry.

Rice husk derived biogenic silica coated cotton as an effective, sustainable oil-water separation platform

Oil-spills present a significant threat to the environmental marine bio-diversity. Conventional cleaning approaches such as skimming are costly. In this regard, alternative approaches utilizing functional nanoparticles (NP) are on the rise due to their effectiveness in separating the non-aqueous phase. This work presents a facile yet sustainable methodology using environmentally-friendly biogenic silica for removing oil from an oil-water mixture. To begin with, an agricultural-waste, rice husk (RH), is subjected to slow pyrolysis under CO2 environment to obtain bio-char. Bio-char is then treated at different pH and calcined, to generate silica NP. Process parameters such as reactor temperature, and pH of biochar-treating solution, are varied to understand their effect on silica NP characteristics. Experiments reveal that pH 5 and temperature 500 °C, facilitate generation of silica NP (∼18 nm). XRD analysis uncovers cristobalite phase presence in NP, which is reported to possess low unit cell volume, thereby contributing to an overall less particle size. Silica NP are modified by treating them with different silanes. PFDS treated silica NP is observed to possess superhydrophobicity, (water contact angle ∼ 160°) and oleophilicity (oil contact angle below 10°). This characteristic is attributed to low surface energy of PFDS. Silica NP coated cotton substrate is then utilized as a sorbent. Repeatability tests reveal that the natural sorbent can effectively separate oil-water mixture even after 40 cycles, with an efficiency of 97%. The findings of this study can aid in development of economical, sustainable platforms for separating oil/water mixtures or harmful components from aqueous/non-aqueous mixture.

Current technologies for plastic waste treatment for energy recovery, it's effects on poly aromatic hydrocarbons emission and recycling strategies

Plastic waste treatment is one of the key challenges faced by many countries. Recycling of the municipal plastic waste for energy recovery is one of the key movements in reduction of plastic waste accumulation. Production of pyrolytic oil and gas products from the plastic waste massive helps to reduce the dependency of fossil fuel. In this review, the exposure of the plastic consumption has been covered. Further, energy recovery methods using the various pyrolysis reactors has been discussed in details. The motive of this review to understand the conversion of plastic waste into value added products such as bio-oil and gas and its consequences in the formation of the polycyclic aromatic hydrocarbons (PAHs) during the handling of municipal plastic waste and e-waste. Besides the impact of PAHs contamination on human health effects also reviewed. Different techniques in converting the plastic waste to energy are discussed in details. Among various pyrolysis methods, microwave assisted pyrolysis possess greater advantage over other process. By varying the type of the feedstock, particle size and temperatures of the reactor, the yield rates can be increased. In addition, by optimizing the reactor temperature their possibility of harmful gaseous products from the plastic waste can be redistricted. Burning of the plastic waste and thermal degradation process releases sixteen types of PAHs compounds to the environment. Inhaling of the PAHs compounds leads to human health effects such as cancer, respiratory diseases and childhood obesity. Thus, an attempt has been made to address the risk of PAHs in the environmental due to the plastic waste handling and its respective human health effects.