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To enhance students' interdisciplinary awareness and understanding of (i) high-pressure reactors, (ii) zeolites as catalysts and (iii) analysis of complex reactor effluents with unknown compounds, the laboratory exercises of two courses are coupled into a cross-curricular Project-Based laboratory Learning trajectory. The alkylation of anisole with 1-hexene proves to be an excellent case study for students to learn new objectives and strengthen the skills acquired in prior courses, emulating the work of expert engineers and analytical chemists. The time-efficient cross-curricular project proves effective in fostering teamwork and addressing complex engineering and analytical challenges. Student testimonials highlight the integrated project's success in providing new insights and cultivating advanced decision-making skills during experimentation. This approach also encourages future interdisciplinary collaborations between chemical engineering and analytical practice classes. [Display omitted] • A cross-curricular project is designed to stimulate interdisciplinary learning. • Coupling chemical reactors and analysis laboratory sessions gives students a more holistic view on reaction engineering. • Alkylation of anisole allows students to relate zeolite properties to catalytic results. • Students reflect that the project has more added value than classical laboratory exercises. • Students perform better in the project than in classical standalone laboratory exercises. [ABSTRACT FROM AUTHOR]

The development of cost effective and environmentally benign adsorbents for arsenic removal is absolutely required due to arsenic contamination of water sources in many regions around the globe. The use of materials which are locally available in the affected regions is important for successful implementation of the developed technologies in rural areas. In this regard, we treated volcanic rocks (red scoria and pumice) locally available in Ethiopia with an aluminum sulphate solution and evaluated these materials for their capacity to remove As(V) from aqueous systems. The adsorbents were characterized using ICP-OES, EDX, SEM and BET. The experimental sorption data fitted well a Freundlich isotherm and the pseudo-second-order model was found to be more suitable than the pseudo-first-order model to describe the adsorption kinetics. The Langmuir maximum adsorption capacity was 0.18 mg/g for aluminum-treated red scoria (Al-Rs) and 2.68 mg/g for aluminum-treated pumice (Al-Pu). The effect of pH, adsorbent dose, initial As(V) concentration and interfering ions on arsenic adsorption were studied. The leaching of aluminum from the adsorbent during the adsorption process was also investigated. Results of column experiments indicated that Al-Pu is suitable to treat low concentration of As(V) contaminated water. The Al-Pu adsorbent is recyclable with only about 9% loss of its original efficiency after the 3 rd adsorption cycle (99.5%–90.2%). The data obtained from both batch and column studies indicate that Al-Rs and Al-Pu remove As(V) effectively from aqueous systems, with the latter being more efficient. [ABSTRACT FROM AUTHOR]

Natural organic matter (NOM) negatively affects water quality and can cause serious issues during water treatment processes. Anion exchange resins (AER) have already proven their effectiveness to remove a major part of this NOM. However, due to its complexity, understanding and improving NOM removal remains challenging. This study aimed to provide in-depth insights in NOM removal with macroporous styrenic weak (WBA), strong (SBA) and combined weak/strong basic AER. Batch experiments were performed with resins in two industrially relevant counter ion forms: OH- and free base form for SBA and WBA resins respectively, using NaOH conditioning, and Cl- form resins using NaCl and HCl conditioning for SBA and WBA resins respectively. Synthetic water containing model compounds for different NOM fractions was used, focussing on the biopolymer fraction which is typically poorly removed by classical ion exchange processes and is a known disinfection by-product precursor in drinking water. The applied resin conditioning procedure influenced the equilibrium pH and consequently NOM removal efficiency and mechanisms. When ion exchange is the dominant driving force for NOM removal, the Cl- form proved to be most efficient. For uncharged NOM containing hydroxyl groups, SBA resins in the OH- form are preferable due to H-bonding. Adsorption of aromatic NOM through π-π interactions with the polystyrene backbone was not affected by the resin conditioning. This work clearly demonstrates that not only the AER type, but also the conditioning procedure and the corresponding counter ion form play a key role in the design of successful NOM removal processes. [Display omitted] • Resin, conditioning procedure and resulting counter ion influence NOM removal. • π-π interactions are involved in the removal of aromatic NOM under all tested conditions. • H-bridges and ion exchange are main interactions based on NOM functionality and pH. [ABSTRACT FROM AUTHOR]

Currently, no mechanistic model is available in wastewater industry that can accurately describe the batch settling behaviour of activated sludge. Such a model, which is based on the fundamental mass and force balances for water and solids, is extended and applied in this work and excellently describes batch settling experiments for sludges originating from two different wastewater treatment plants. The mechanistic model contains a Kynch batch density function (hindered settling) and an effective solids stress function (compression). Initial settling velocities were obtained from detailed spatio-temporal dynamic solids concentration profiles measured with the aid of a radiotracer [De Clercq, J., Jacobs, J., Kinnear, D.J., Nopens, I., Dierckx, R.A., Defrancq, J., Vanrolleghem, P.A., 2005. Detailed spatio-temporal solids concentration profiling during batch settling of activated sludge using a radiotracer. Water Res. 39(10), 2125–2135]. Moreover, inverse modelling calculations were performed using the same data set. Both calculations showed that (1) the power function of Cole gave acceptable results and (2) a single effective solids stress function could be found when a time-dependent compression solids concentration was considered. This compression solids concentration is found just below the sludge blanket and is readily calculated from the solids concentration profiles. Given these time-evolutions, the effective solids stress values exhibit a uniform logarithmic relationship with the difference between the solids concentration and the compression solids concentration. The descriptive power of the model indicates a good potential for wider applicability of the model. [Copyright &y& Elsevier]

Abstract: In building and tuning good settling models for secondary clarifiers of wastewater treatment plants, there is a need for measured continuous solids concentration profiles during batch settling. Conventional measuring techniques have difficulties in recording this kind of data, either because they are invasive, or because of the low solids concentration and/or solids density of activated sludge. This paper investigates a novel non-invasive measurement technique borrowed from nuclear medicine, using a solids radiotracer and gamma cameras, to obtain solids concentration profiles during the batch settling of activated sludge, in a pilot-scale column with a height of 1m. The technique does not disturb the settling process, does not alter the settling characteristics, gives profiles every minute and every few millimeters, and is capable of measuring in a range of 0–25g/l with high accuracy. Dynamic solids concentration profile measurements were performed for sludges of different wastewater treatment plants, and at different initial concentrations. The results show a quantitative representation of the settling process, and reveal hindered and compression settling. [Copyright &y& Elsevier]

Mesoporous MIL-101(Cr) is used as host for a ship-in-a-bottle type adsorbent for selective U(VI) recovery from aqueous environments. The acid-resistant cage-type MOF is built in-situ around N,N-Diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO), a sterically demanding ligand with high U(VI) affinity. This one-step procedure yields an adsorbent which is an ideal compromise between homogeneous and heterogeneous systems, where the ligand can act freely within the pores of MIL-101, without leaching, while the adsorbent is easy separable and reusable. The adsorbent was characterized by XRD, FTIR spectroscopy, nitrogen adsorption, XRF, ADF-STEM and EDX, to confirm and quantify the successful encapsulation of the CMPO in MIL-101, and the preservation of the host. Adsorption experiments with a central focus on U(VI) recovery were performed. Very high selectivity for U(VI) was observed, while competitive metal adsorption (rare earths, transition metals...) was almost negligible. The adsorption capacity was calculated at 5.32 mg U/g (pH 3) and 27.99 mg U/g (pH 4), by fitting equilibrium data to the Langmuir model. Adsorption kinetics correlated to the pseudo-second-order model, where more than 95% of maximum uptake is achieved within 375 min. The adsorbed U(VI) is easily recovered by desorption in 0.1 M HNO 3 . Three adsorption/desorption cycles were performed. [ABSTRACT FROM AUTHOR]

• Computational nucleophilicity probing of amines for the aldol reaction. • Trimethylborane (TMB) probes steric and electronic substituent effects on amines. • The experimental activity of hindered amines in the aldol reaction can be described. • New amine sites with an optimized TMB basicity are designed for the aldol reaction. Accessibility of the nucleophilic site in organocatalysts is essential to ensure adequate catalytic activity. Gas-phase trimethylborane (TMB) Lewis basicity and Brønsted proton basicity of several amine based organocatalysts have been calculated using the CBS-QB3 model chemistry. This TMB basicity scale can, as opposed to the proton basicity scale, account for steric effects encountered in the initial nucleophilic attack of the nitrogen free electron pair on a substrate. Since such a step is the first one in several amine catalyzed reactions, severe steric hindrance of the nucleophilic center would render the catalyst ineffective. Comparing the TMB basicity and proton basicity with the experimentally observed catalytic activity of both homogeneous and heterogeneously supported amine sites found in literature for the aldol reaction of acetone with 4-nitrobenzaldehyde showed that, due to the inclusion of these steric effects, the TMB basicity scale is a much better predictor of catalytic activity than the proton basicity. According to this computational Lewis basicity scale, potential steric hindrance in alternative nitrogen containing active sites was probed. This resulted in 3-propylpyrrolidine being proposed among the most promising monofunctional amine groups and 1-(methylamino)propan-2-ol among the most promising bifunctional amine-hydroxyl groups for heterogeneous aldol reaction catalysts. [ABSTRACT FROM AUTHOR]

An uncalcined HT supported Pd-NP catalyst was synthesized via co-precipitation, i.e., PdHT_100RED_20, and benchmarked against a Pd impregnated HT catalyst, i.e., Pd@HT_500RED_20. TEM analysis pointed out that the largest NPs (6.5 nm) were found in the co-precipitated catalyst because of its weaker steric NP confinement, compared to the benchmark catalyst (3.2 nm). The PdHT_100RED_20 had a significantly higher catalytic performance (60% conversion, 1.85% leaching) than Pd@HT_500RED_20 (19%, 0.98%) due to lack of calcination resulting in an ordered, and thus, more accessible HT structure in combination with its high support basicity. Both catalysts showed low Pd leaching confirming the suitability of HTs as NP support. Focusing on PdHT_100, the effect of the reduction temperature on the NP size and catalytic performance was investigated. NP size distribution analysis showed that the smallest NPs were found in PdHT_100RED_0 (5.3 nm), resulting in a higher catalytic performance (67%, 2.28%) when compared to PdHT_100RED_20 (6.5 nm). Performing the reduction at higher temperatures, i.e., at 60 °C (5.7 nm), caused an extremely low catalytic performance (13%, 0.20%) due to the less efficient reduction reaction with NaBH 4 at higher reduction temperatures. Reusing PdHT_100RED_20, a decrease in catalytic performance (45%) was observed. However, this decrease was less pronounced (50%) when a re-activation of the catalyst with Na 2 CO 3 between consecutive runs was performed. Moreover, it was shown that the leached Pd species were able to re-deposit onto the support if high conversions were obtained, and thus, an almost quantitatively recovery from the reaction mixture can be achieved with retention of its catalytic activity (>99%). [ABSTRACT FROM AUTHOR]

Mesoporous carbons have been the subject of various studies, both fundamental and applied. Fundamental studies revealed numerous synthesis routes which can adjust material characteristics as specific surface area, pore volume, pore size or morphology and elemental composition. The indirect synthesis or hard template method was developed first. An extensive collection of template materials exist, which can be impregnated with carbon precursors to provide various hard templated mesoporous carbons with a precise control of mesoporosity and pore geometry. However, the more recent direct method or soft template method offers some specific advantages. By using the organic-organic self-assembly between polymerizable precursors and block copolymer surfactants as structure directing agents it is possible to obtain tunable morphology and surface properties, mechanical stability and reduce the number of synthesis steps, thereby decreasing synthesis cost and complexity. Applied studies valorize this wide variety of mesoporous carbons. Fine-tuning material characteristics as surface area, pore volume, pore size, morphology, chemical composition or possible post-modification or nanoparticle doping give rise to applications in catalysis, electrochemistry, energy storage, separation or adsorption. In adsorption, mesoporous carbons are considered as a new family of adsorbents challenging the well-known activated carbon by introducing the advantage of increasing pore size. This allows mesoporous carbons to adsorb larger molecules and enhance the adsorption kinetics. In this review we present the most recent achievements and advances in the synthesis of soft templated mesoporous carbons, with focus on pore size control, and their potential as a new family of carbon adsorbents. [ABSTRACT FROM AUTHOR]

[Display omitted] • n -Alkane hydrocracking is more negatively impacted with admixture of heavier cycloalkanes. • Cycloalkane adsorbs on metal sites more favorably than n -alkane with higher carbon number. • Larger alkanes impact cycloalkanes conversion only by preferred physisorption. Cycloalkanes are known to impact the metal–acid balance of the hydrocracking of n -alkanes with similar carbon number, however, how this impact varies with the carbon number of the components involved is still to be understood in more detail. For this purpose, the hydroconversion of n -octane and tert -butylcyclohexane, and n -decane and methylcyclohexane mixtures was investigated in this work over Pt/HUSY catalyst in both the ideal and the nonideal hydrocracking regime. Irrespective of the hydrocracking regime for pure n -octane, its conversion and isomer yields were significantly lowered upon admixture of tert -butylcyclohexane. On the other hand, n -octane admixture did not impact the tert -butylcyclohexane conversion nor its cyclic isomer yields. Upon methylcyclohexane admixture with n -decane, no impact was observed over the catalyst ensuring ideal hydrocracking of pure n -decane. Over the catalyst with significantly lower Pt loading, which does not ensure ideal hydrocracking of n -decane, methylcyclohexane lowered the n- decane conversion. A slightly negative impact of n -decane admixture on methylcyclohexane conversion was also observed. The observed effects are mainly attributed to the differences in adsorption strengths within the zeolite pores on top of differences in alkane and cycloalkane adsorption on the metal sites. [ABSTRACT FROM AUTHOR]