South African Journal of Chemical Engineering最新文献

{"title":"TiO2-encapsulated CdS heterointerface enables directional charge transfer and suppresses detectable Cd2+ leaching during solar tetracycline degradation","authors":"Ahed H. Zyoud","doi":"10.1016/j.sajce.2026.101012","DOIUrl":"10.1016/j.sajce.2026.101012","url":null,"abstract":"<div><div>The development of stable semiconductor heterointerfaces that improve charge separation while reducing photocorrosion in visible-light photocatalysis remains challenging. In this work, a buried CdS/TiO₂ heterointerface was created by sequential deposition of a nanocrystalline CdS sensitizing layer followed by full coverage with a rutile TiO₂ overlayer. XRD revealed crystalline phases, whereas SEM, cross-sectional SEM, and AFM supported the continuous layered morphology and interfacial contact. Mott–Schottky, transient photocurrent, and PL/TRPL measurements supported efficient interfacial electron extraction from photoexcited CdS into TiO₂ with reduced charge‒carrier recombination. Tetracycline degradation under simulated solar irradiation reached 96.3% under optimal conditions. Both the pseudo-first-order and pseudo-second-order models described the degradation data well, with a slightly better fit for the latter, whereas the Arrhenius analysis gave an apparent activation energy of 7.56 kJ mol⁻¹. The degradation efficiency of the heterostructure was &gt;91% after five consecutive reuse cycles, indicating good short-term operational stability. The dissolved Cd²⁺ concentrations remained below the analytical detection limit throughout the photocatalytic operation, which is consistent with the effective suppression of CdS photocorrosion by TiO₂ encapsulation. These findings show that buried-interface engineering can integrate visible-light sensitization, favorable interfacial charge extraction, photocatalytic activity, and protection of a photocorrosion-prone sensitizer within a single immobilized architecture.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"58 ","pages":"Article 101012"},"PeriodicalIF":6.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149141037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, fabrication, and validation of a low-cost open-source multi-sensor automatic titrator with gravimetric titrant delivery for real-time endpoint and enthalpy determination","authors":"Nuttawisit Yasarawan,&nbsp;Pichamon Jittaviriyapong,&nbsp;Kanoksak Saelee,&nbsp;Akapong Suwattanamala,&nbsp;Supranee Kaewpirom,&nbsp;Takat Benjalersyarnon,&nbsp;Teeranan Nongnual","doi":"10.1016/j.sajce.2026.101025","DOIUrl":"10.1016/j.sajce.2026.101025","url":null,"abstract":"<div><div>Acid–base titration underpins analytical measurement across the chemical and process industries, yet in teaching laboratories it is still performed with a manual buret that yields sparse data points and subjective visual endpoints, while commercial automatic titrators remain too costly and closed for widespread hands-on use. We report the design, fabrication, and validation of a Multi-Sensor Automatic Titrator (MSAT): a low-cost, open-hardware instrument developed as a hands-on platform for chemical engineering education. An ESP32 microcontroller with 3D-printed probe mounts integrates four endpoint-detection channels (potentiometric pH, conductometric, colorimetric, and thermometric), titrant is metered gravimetrically by a load cell, and all channels are logged at 2 Hz against a common time-and-mass axis. A web-based controller runs the titration and a companion Python analyzer extracts equivalence points, <em>pK_a</em> values, and reaction enthalpies. Synchronous four-channel logging lets students watch the probes jointly locate and cross-validate every equivalence point, with the thermometric channel resolving final endpoints in overlapping-<em>pK_a</em> polyprotic systems. Across nine acid–base systems (potassium hydrogen phthalate (KHP), HCl, H₂SO₄, H₃PO₄, oxalic, malic, succinic, citric, benzoic), the colorimetric, conductometric, and thermometric channels showed no significant difference from the potentiometric reference and were equivalent to it within ±1 % of titrant (paired <em>t</em>-tests, <em>p</em> &gt; 0.05; two one-sided equivalence tests (TOST), <em>p</em> &lt; 0.001; Pearson <em>r</em> &gt; 0.999; <em>N</em> = 21–86); mole ratios matched theory within ±5 %, and calorimetric enthalpies agreed with reference values to within 11 %. The complete hardware, firmware, and analysis pipeline are released open-source as a reproducible, extensible teaching resource.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"58 ","pages":"Article 101025"},"PeriodicalIF":6.3,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149199582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Barium and F-TiO2-incorporated metal-organic framework electrodes for supercapacitors","authors":"Preema Cealla Pais,&nbsp;Ronald Aquin Nazareth,&nbsp;Y.N. Sudhakar,&nbsp;Nakul Desai","doi":"10.1016/j.sajce.2026.100927","DOIUrl":"10.1016/j.sajce.2026.100927","url":null,"abstract":"<div><div>This study presents a novel metal organic framework (MOF-199) based composites synthesized under two conditions: room temperature (RCMBF) and hydrothermal (HCMBF). Initially, MOF-199 was doped with barium, followed by fluorine-doped titanium dioxide (F-TiO₂) to form the final composites. These materials were combined with activated carbon (AC) to fabricate asymmetric supercapacitor cells, enhancing the energy storage performance. Dual doping improved the ionic conductivity and electrochemical behavior. Structural and morphological analysis, such as scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS) confirmed the octahedral MOF-199 morphology in the pristine MOFs and composite coarseness. X-ray diffraction (XRD) revealed sharp 2θ peaks, indicating high crystallinity. Fourier transform infrared spectroscopy (FTIR) and thermal gravimetric analysis (TGA) revealed strong interactions between the dopants and MOF-199, confirming their thermal and chemical stability. Brunauer-Emmett-Teller (BET) analysis showed progressive reduction in surface area due to layer-by-layer stacking. Xray photoelectron spectroscopy (XPS) revealed excellent interactions between dopants and MOF framework. Electrochemical tests revealed that in a three-electrode system, the RCMBF achieved a specific capacitance of 67 F g⁻¹, whereas the HCMBF reached 57 F g⁻¹. In a two-electrode system with AC, RCMBF delivered 123 F g⁻¹, and the HCMBF delivered 68 F g⁻¹ via cyclic voltammetry (CV). Electrochemical impedance spectroscopy (EIS) analysis revealed that the RCMBF electrode had less resistance than the HCMBF electrode. Galvanostatic charge discharge (GCD) tests at 0.07 mA g⁻¹ revealed that the RCMBF/AC achieved values of energy and power densities of 1.5 Wh kg⁻¹ and 126 kW kg⁻¹, respectively. At a current density of 0.02 mA g⁻¹, HCMBF/AC yielded 1.8 Wh kg⁻¹ and 45 kW kg⁻¹. At 10,000 cycles, the RCMBF/AC system demonstrated 79% retention, whereas the HCMBF/AC system showed 61% retention. The columbic efficiencies were 94% (RCMBF) and 83% (HCMBF) respectively. These results demonstrate the potential of Ba/F-TiO₂-doped MOF-199 composites for high-performance, eco-friendly supercapacitor applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100927"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148553709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A bioinspired irreversibility analysis of ternary nanofluid stream in electroosmotic divergent conduit under radiative-convective effects","authors":"Najma Saleem,&nbsp;Noreen Sher Akbar,&nbsp;S. Ijaz,&nbsp;Dharmendra Tripathi,&nbsp;Sumiya Nasir","doi":"10.1016/j.sajce.2026.100923","DOIUrl":"10.1016/j.sajce.2026.100923","url":null,"abstract":"<div><div>Hybrid nanofluids have emerged as highly effective working fluids in modern thermal engineering due to their exceptional heat transfer aspects. Their capability to enhance efficiency in heating and cooling systems has established them as preferred choice across the wide range of heat management applications. The purpose of this study is to investigate the thermal and flow behavior of a magneto-radiative ternary nanofluid composed of copper, silver, and alumina nanogranules dissolved in blood as base fluid. The intended flow is inspected through a stretchy diverging surface in the presence of electroosmotic forces, momentum and thermal wall slip conditions. The governing equations formulated in wave frame are simplified under small inertia and long wavelength approximations. Numerical solutions of the resulting nonlinear equations are obtained via the shooting technique implemented in Mathematica software. The graphical results offer a comprehensive insight into the flow dynamics. Findings reveal that considerable magnetic effects and an expanded width of electric double layer tend to suppress the fluid motion while leading to an upsurge in temperature close to the channel core part. Additionally, integration of thermal radiation effects, boundary slip effects, and thickened electric double layer contributes to reduction in heat losses inside the channel. A drop in entropy generation and an increment in the Bejan number communicate better heat transfer proficiency and discriminating irreversibility within the flow. Furthermore, the ternary hybrid nanofluid returns the highest enhancement in heat transfer rate compared to conventional blood, thus making it a promising medium for microfluidic and biomedical applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100923"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148553814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the effects of heat absorption and chemical reaction in MHD flow of upper-convected Maxwell nanofluid over a bidirectional stretching surface with gyrotactic microorganisms: A comparative study","authors":"Muhammad Jawad,&nbsp;Ali Basem,&nbsp;Aaqib Majeed,&nbsp;Gabriella Bognár","doi":"10.1016/j.sajce.2026.100937","DOIUrl":"10.1016/j.sajce.2026.100937","url":null,"abstract":"<div><div>This study investigates the three-dimensional magnetohydrodynamic (MHD) flow of an upper-convected Maxwell nanofluid over a bidirectional stretching surface, incorporating motile microorganisms, nonlinear thermal radiation, chemical reaction, and heat absorption. A comparative analysis between non-Newtonian (Maxwell) and Newtonian nanofluids is performed. The governing nonlinear partial differential equations are reduced to ordinary differential equations via similarity transformations and solved numerically using the bvp4c solver in MATLAB. Key findings demonstrate that increasing the magnetic parameter and Deborah number reduces both axial and transverse velocity components. Higher thermal radiation and thermophoresis parameter elevate the temperature profile. An increase in the chemical reaction parameter and Lewis number significantly reduces nanoparticle concentration. The Brownian motion parameter enhances temperature while reducing concentration. The Nusselt number increases with Prandtl number and decreases with thermophoresis, whereas the Sherwood number declines with both parameters. Increasing the Peclet number reduces the motile microorganism density. Compared to Newtonian nanofluids, the non-Newtonian Maxwell nanofluid exhibits higher temperature yet lower heat transfer rate.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100937"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing binary extraction solvent mixture and computer-aided simulation perspective for nutraceutical extract production from Ajumbaise South-Eastern poly-herbal formulation using sequential two-pot extraction technology","authors":"E. O. Oke,&nbsp;Okereke Eze Aru,&nbsp;D. Nnabodo,&nbsp;O. Adeyi,&nbsp;J. A. Adeyi,&nbsp;U. N. Onuoha,&nbsp;C. J. Ude,&nbsp;A. A. Adeyemo,&nbsp;Solomon N. Ijioma,&nbsp;Mathew Odo,&nbsp;Okonkwo Chimaobi K․","doi":"10.1016/j.sajce.2026.100935","DOIUrl":"10.1016/j.sajce.2026.100935","url":null,"abstract":"<div><div>Aju-Mbaise Polyherbal (AMP) formulation has been consumed by Nigerian folks to cure some pathological disorders in human system. Previous studies have documented the biological, pharmacological, and antioxidant activities of AMP extract; however, the multi-response optimization of extraction solvent mixtures, process parameters, and the scale-up of hybrid microwave-assisted and conventional heat-assisted extraction technologies remain unreported in the literature. Therefore, this investigation aims to optimize the extraction solvent mixture and process parameters for the technology scale-up analysis of extract production. In this study, Simplex-Lattice Mixture (SLM) design and Box-Behnken Response Surface Methodology (BBRSM) were employed to optimize the extraction solvent mixture and process parameters for the hybrid extraction of AMP. ASPEN simulator was also used for computer-aided process simulation and the scale-up perspective. The regression models for the prediction of extraction solvent mixture and process parameters gave coefficient of determination (R2) of 0.98 and 0.99 respectively with adjusted R2 of 0.970 and 0.961 accordingly. The optimum extraction solvent mixture was 25 % ethanol and 75 % water, while the optimal process variables: extraction time (69.5 min), temperature (75 °C), and solid–liquid ratio (0.88 g/mL) yielded an extractible yield of 25.2 %, TPC of 16.2 mg GAE/g d.w., TFC of 4.88 mg rutin/g d.w., and DPPH of 9.46 mg AAE/g d.w. High-performance-liquid-chromatograph revealed the presence of betullin acid, gallic acid, caffeic acid and rutin compounds in the extract. ASPEN base case scale-up simulation result was compared experimentally and gave MSE, RMSE and MAPE gave 0.0069, 0.082 and 0.09 respectively. The scale-up process design (3900kg/year) results gave batch size (0.87 kg), batch time (167 mins) and production rate (5.14 g/mins). This study showed that computer-aided simulation of sequential MAE and conventional HAE technology is feasible.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100935"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic effects of silver doping in tin oxide on structural, optical and photocatalytic properties: a combined first principles and experimental validation study","authors":"Habtamu F. Etefa,&nbsp;Francis B. Dejene","doi":"10.1016/j.sajce.2026.100933","DOIUrl":"10.1016/j.sajce.2026.100933","url":null,"abstract":"<div><div>This study combines Density Functional Theory (DFT) calculations and experimental investigations to elucidate the structural, electronic, and optical properties of pristine and Ag-doped tetragonal SnO₂. The DFT calculations were performed using the PBE exchange-correlation functional with Hubbard U corrections (DFT+U). A SnO₂ supercell was constructed, with Ag substituting Sn atoms at concentrations of 3.125%, 6.25%, and 12.5%. Experimentally, pristine SnO₂ nanoparticles were synthesized via a precipitation method, while Ag-doped SnO₂ nanocomposites were prepared by incorporating biosynthesized Ag nanoparticles, followed by annealing at 400 °C. Structural characterization and DFT results demonstrated excellent agreement, confirming the stability of the tetragonal SnO₂ framework upon Ag incorporation. The presence of Sn⁴⁺, O²⁻, and surface hydroxyl species was verified, indicating favorable surface characteristics for photocatalytic applications. Both theoretical and experimental analyses revealed a progressive reduction in band gap with Ag doping, from 2.97 eV (DFT) and 2.99 eV (experimental) for pristine SnO₂ to 2.70 eV (DFT) and 2.71 eV (experimental) for 6.25% Ag-doped SnO₂. This band-gap narrowing was accompanied by enhanced visible-light absorption and improved electronic properties. Among the investigated compositions, 6.25% Ag-doped SnO₂ exhibited the most favorable performance, highlighting the beneficial role of Ag-induced electronic modifications. These findings demonstrate that Ag doping is an effective strategy for tailoring the optical and electronic properties of SnO₂, making it a promising material for visible-light-driven photocatalysis and solar energy conversion applications.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100933"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148553715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD-driven machine learning prediction of heat transfer enhancement of ternary hybrid nanofluids in turbulent mixed convection channel flow","authors":"M. Gopika,&nbsp;R. Harish,&nbsp;N. Vishnu Ganesh","doi":"10.1016/j.sajce.2026.100931","DOIUrl":"10.1016/j.sajce.2026.100931","url":null,"abstract":"<div><div>Turbulent mixed convection in vertical channels plays a critical role in the thermal management of compact heat exchange systems, electronic cooling and energy transport devices. However, the coupled influence of buoyancy-driven turbulence and ternary hybrid nanofluids remains insufficiently explored, particularly for predictive data-driven modeling. In this study, a CFD-driven machine learning framework is developed to investigate heat transfer enhancement in turbulent mixed convection of ternary hybrid nanofluids flowing through a differentially heated vertical channel. The investigations are performed for both assisting and opposing flow configurations over a Richardson number range of <span><math><mrow><mn>0</mn><mo>.</mo><mn>01</mn><mo>≤</mo><mi>R</mi><mi>i</mi><mo>≤</mo><mn>1</mn></mrow></math></span>, considering different nanoparticle combinations and volume fractions. The results show that assisting flow conditions significantly enhance convective heat transfer due to the constructive interaction between buoyancy and forced convection, whereas opposing flow conditions promote thermal stratification and reduced heat transfer. All ternary hybrid nanofluids outperform pure water, with the Al<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>O<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span> <img>Cu<img>MoS<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> formulation consistently exhibiting the highest thermal performance. Under assisting flow conditions, increasing the nanoparticle volume fraction from 1.5% to 6% enhances the average Nusselt number by up to 52.97% at <span><math><mrow><mi>R</mi><mi>i</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>01</mn></mrow></math></span>, while increasing the Richardson number further amplifies heat transfer due to the growing dominance of buoyancy-induced convection. In opposing flow, nanoparticle loading improves heat transfer by up to 45.58%, whereas increasing <span><math><mrow><mi>R</mi><mi>i</mi></mrow></math></span> leads to a mild deterioration due to buoyancy-induced flow deceleration. To enable rapid prediction of heat transfer performance, artificial neural network models trained using Levenberg–Marquardt and L2-regularized Adam optimization strategies are developed based on CFD data. Both models accurately predict the Nusselt number, with the L2-regularized Adam model demonstrating superior robustness across strongly nonlinear flow regimes.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100931"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational analysis of sodium alginate-based Casson hybrid carbon nanotubes over a stretching/shrinking cylinder: An ANN approach","authors":"Shilpa,&nbsp;S. Eswaramoorthi,&nbsp;Saleem Nasir,&nbsp;K. Loganathan,&nbsp;Abdallah Berrouk","doi":"10.1016/j.sajce.2026.100936","DOIUrl":"10.1016/j.sajce.2026.100936","url":null,"abstract":"<div><div>Carbon nanotubes (CNTs) are incredibly versatile nanomaterials due to their exceptional electrical, mechanical, and chemical properties. Their broad surface area, as well as their excellent conductivity, enable the design of novel sensors capable of detecting a wide variety of drugs and polymers with outstanding sensitivity and precision. Based on these, the current study focused on the radiative MHD Casson hybrid CNTs for stagnation-point flow past a shrinkable/stretchable cylinder, with heat generation/consumption and Joule heating. The single-wall carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs) are immersed in sodium alginate (SA) to boost up the thermal conductivity of the base fluid. Suitable transformations are applied to convert the governing mathematical models into ordinary differential equation models, which are then numerically solved using the bvp4c scheme in MATLAB. In addition, the skin friction coefficient and local Nusselt number are investigated through the Bayesian regularization neural network (BRNN) approach. The mean squared error and error histogram are used to evaluate the performances. In this approach, 70% of data points are used in training and 15% of data points are used in both the testing and validation processes. The inspiration of numerous governing parameters on flow dynamics and thermal profile is analyzed through graphs. It is noticed that the fluid velocity declines when increasing the values of the nanoparticle volume fraction. The thermal profile escalates when increasing the values of the Eckert number, radiation and nanoparticle volume fraction parameters. These kind of mathematical research is important in many engineering and industrial areas, including cooling thermal equipment, heat exchanges, power plants, wire-drawing, thermal therapies, etc.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100936"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Amorphous silica alumina supported nickel sulfide catalysts for tunable hydrocracking of crude palm oil to biofuel","authors":"Hasanudin Hasanudin,&nbsp;Wiwik Siscia Asany,&nbsp;Akhmad Syoufian,&nbsp;Karna Wijaya,&nbsp;Ahmad Mudzakir,&nbsp;Ahmad Suseno,&nbsp;Nino Rinaldi,&nbsp;Erwan Hermawan,&nbsp;Wan Ryan Asri,&nbsp;Mohammad N. Siddiqui,&nbsp;Tawfik A. Saleh","doi":"10.1016/j.sajce.2026.100939","DOIUrl":"10.1016/j.sajce.2026.100939","url":null,"abstract":"<div><div>The development of efficient catalysts for hydrocracking of crude palm oil (CPO) remains important for improving the production of renewable hydrocarbon fuels. This study investigates the hydrocracking of CPO over amorphous potassium hydrogen phthalate (KHP)‒templated Si/Al catalysts modified with NiO and NiS, and proposes structure‒activity relationships supported by detailed physicochemical characterization and response surface methodology (RSM). Nickel impregnation and sulfidation form well dispersed NiO and NiS domains without disrupting the mesoporous Si/Al framework. Acidity analysis reveals that all catalysts lacked medium-strength acid sites, and sulfidation generates a surface dominated by weak acid sites while retaining a small fraction of strong acid sites. Catalytic screening indicates that KHP‒Si/Al‒NiS exhibits the highest conversion (78.58 %) and the most favorable biofuel distribution, producing 44.14 % C₅‒C₉, 30.44 % C₁₀‒C₁₄, and the lowest C₂₂₊ fraction (9.26 %), demonstrating the potential of the KHP‒Si/Al‒NiS catalyst as an alternative sulfided catalyst system for hydrocracking by combining the catalytic functionality of NiS with the structural stability of the amorphous mesoporous Si/Al support. RSM‒CCD was then applied to optimize reaction conditions over KHP‒Si/Al‒NiS, revealing temperature and feed flow rate as the dominant variables controlling both conversion and biogasoline fraction. The optimized reaction conditions (677 °C, 11.12 g/min feed flow rate, and 4 g of catalyst) afford 84.30 % conversion and 44.55 % biogasoline fraction. The observed acidity distribution suggests that the predominance of weak acid sites after sulfidation, together with the remaining strong acid sites, contributes to the formation of C₅‒C₁₄ hydrocarbons while limiting excessive over-cracking, demonstrating the potential of the catalyst system for tunable biofuel production through process optimization of the hydrocracking operating conditions.</div></div>","PeriodicalId":21926,"journal":{"name":"South African Journal of Chemical Engineering","volume":"57 ","pages":"Article 100939"},"PeriodicalIF":6.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148539600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}