Activated carbon from pyrolysis of brewer's spent grain: Production and adsorption properties.

Brewer's spent grain is a low cost residue generated by the brewing industry. Its chemical composition (high nitrogen content 4.35 wt.%, fibres, etc.) makes it very useful for the production of added value in situ nitrogenised activated carbon. The composition of brewer's spent grain revealed high amounts of cellulose (20.8 wt.%), hemicellulose (48.78 wt.%) and lignin (11.3 wt.%). The fat, ethanol extractives and ash accounted for 8.17 wt.%, 4.7 wt.% and 3.2 wt.%, respectively. Different activated carbons were produced in a lab-scale pyrolysis/activation reactor by applying several heat and steam activation profiles on brewer's spent grain. Activated carbon yields from 16.1 to 23.6 wt.% with high N-contents (> 2 wt.%) were obtained. The efficiency of the prepared activated carbons for phenol adsorption was studied as a function of different parameters: pH, contact time and carbon dosage relative to two commercial activated carbons. The equilibrium isotherms were described by the non-linear Langmuir and Freundlich models, and the kinetic results were fitted using the pseudo-first-order model and the pseudo-second-order model. The feasibility of an activated carbon production facility (onsite and offsite) that processes brewer's spent grain for different input feeds is evaluated based on a techno-economic model for estimating the net present value. Even though the model assumptions start from a rather pessimistic scenario, encouraging results for a profitable production of activated carbon using brewer's spent grain are obtained.

Biochar improves the nutrient cycle in sandy-textured soils and increases crop yield: a systematic review.

BACKGROUND: Biochar is a relatively new development in sustainable agricultural management that can be applied to ameliorate degraded and less fertile soils, especially sandy-textured ones, to improve their productivity with respect to crop production through improved nutrient availability. However, as the literature has shown, the response of sandy-textured soils to biochar varies in terms of effect size and direction. Therefore, the present study systematically reviewed the available evidence to synthesize the impact of biochar amendments on aspects of the nutrient cycle of sandy-textured soils. METHODS: Both peer-reviewed and gray literature were searched in English in bibliographic databases, organizational web pages, and Internet search engines. Articles underwent a two-stage screening (title and abstract, and full-text) based on predefined criteria, with consistency checks. Validity assessments were conducted, utilizing specifically designed tools for study validity. Data extraction involved categorizing the various properties of the nutrient cycle into nine main Soil and Plant Properties (SPPs), each of which was studied independently. Nine meta-analyses were performed using a total of 1609 observations derived from 92 articles. Comparing meta-averages with and without correction for publication bias suggests that publication bias plays a minor role in the literature, while some indication for publication bias is found when accounting for heterogeneity by means of meta-regressions. REVIEW FINDINGS: According to the results, soil total and available nitrogen [N], phosphorous [P] and potassium [K], plant nutrient level, and potential cation exchange capacity (CEC) increased by 36% (CI [23%, 50%]), 34% (CI [15%, 57%]), 15% (CI [1%, 31%]), and 18% (CI [3%, 36%), respectively, and N2O emission and mineral nutrient leaching decreased by 29% (CI [- 48%, - 3%]) and 38% (CI [- 56%, - 13%). On average, however, biochar had no effect on soil mineral nitrogen and nutrient use efficiency. Publication bias was identified in the response of effective CEC. After corrections for publication bias, the response shifted from 36% to a negative value of - 34% (CI [- 50%, - 14%]). Meta-regression found that the effect modifiers experimental continent, biochar application rate, and soil pH, explain result heterogeneity. Stronger responses came from the continent of South America, higher application rates, and higher pH soils. Overall, biochar is found useful for many SPPs of nutrient cycling of sandy-textured soils, thereby contributing to increased crop yields in such soils.

A DFT conformational analysis and VCD study on methyl tetrahydrofuran-2-carboxylate.

DFT calculations were performed on (S)-methyl tetrahydrofuran-2-carboxylate to facilitate the interpretation of IR and VCD spectra. The potential energy surface could not be described unambiguously using the 6-31G* basis set in combination with different density functionals including B1LYP, B3LYP, B3P86, B3PW91, B98, BHandH, BHandHLYP, MPW1PW91 and PBE1PBE. In contrast, a uniform conformational picture could be found using the cc-pVTZ basis set. Using this large basis set and the collection of nine functionals from above, the dipole and rotational strengths were calculated, and compared to experimental values which were extracted from the experimental IR and VCD spectra for (+)-(S)-methyl tetrahydrofuran-2-carboxylate. A detailed analysis on the agreement between experiment and simulated spectra was performed by assigning the experimental bands based on the harmonic fundamentals obtained for all functionals except BHandH, which performs badly over the whole line. Assessing the dipole strengths, all tested functionals perform equally well. For the rotational strengths, differences can be observed: B3LYP, B1LYP and B98 give the highest correlation with experiment, while PBE1PBE gives the lowest correlation. Comparable conclusions are obtained using a neighborhood similarity measure.

Determination of absolute configuration via vibrational circular dichroism.

Vibrational circular dichroism (VCD) provides a growing and promising technology for the determination of the absolute configuration of molecules in solution, including drug molecules. The practical application of VCD spectroscopy consists of the experimental determination and comparison to quantum chemically calculated data. The key features of the VCD technology are presented and an example of an application of the technique is discussed.:

Economics of willow pyrolysis after phytoextraction.

The Campine is a vast cross-border area in the northeast of Belgium and southeast of the Netherlands that has been contaminated with heavy metals. As traditional excavation techniques are too expensive, phytoremediation is preferred. Economically viable conversion techniques for the biomass are researched in order to lower reclamation costs and to guarantee the income of the local farmers, mainly cultivating roughage for dairy cattle rearing. Energy generation by means of pyrolysis of willow from short-rotation coppice seems to be very interesting. This article aims to search for the maximum possible biomass price so that the net present value of the profits stemming from energy conversion based on pyrolysis is at least positive.

Intermolecular association of tetrahydrofuran-2-carboxylic acid in solution: a vibrational circular dichroism study.

Carboxylic acids are known for their strong intermolecular associations. With chiral carboxylic acids, this behavior can be studied using vibrational circular dichroism (VCD). Tetrahydrofuran-2-carboxylic acid 1, a chiral building block for beta-lactam antibiotics, is studied by emphasizing the effect of the dimerization. Experimental results indicate that for solutions of 1 in CDCl3 and CS2, a complex equilibrium exists between the monomers and dimers. B3LYP/aug-cc-pVTZ calculations are performed on both monomer and dimer structures. To simulate IR and VCD spectra, populations for monomer and dimers were approximated using a semiquantitative model. A good agreement between experimental and simulated spectra is obtained by taking into account both the monomeric and the dimeric structures, weighted using the experimentally determined populations.

Elucidation of the absolute configuration of JNJ-27553292, a CCR2 receptor antagonist, by vibrational circular dichroism analysis of two precursors.

The absolute configurations of two precursors, that is, 1-(3',4'-dichlorophenyl)-propanol and 1-(3',4'-dichlorophenyl)-propanamine, of a potent 2-mercapto-imidazole CCR-2 receptor antagonist, JNJ-27553292, were determined using vibrational circular dichroism. As a consequence, the absolute configuration of the antagonist itself was also determined. The two precursor compounds were subjected to a thorough conformational analysis and rotational strengths were calculated at the B3LYP/cc-pVTZ level of theory. Based on these data, vibrational circular dichroism spectra were simulated, which in turn were compared with experimental spectra. Agreement between the spectra allowed the assignment of the absolute configuration, which is in agreement with the proposed configuration based on stereospecific reactions on similar compounds.

Quantum similarity superposition algorithm (QSSA): a consistent scheme for molecular alignment and molecular similarity based on quantum chemistry.

The use of the molecular quantum similarity overlap measure for molecular alignment is investigated. A new algorithm is presented, the quantum similarity superposition algorithm (QSSA), expressing the relative positions of two molecules in terms of mutual translation in three Cartesian directions and three Euler angles. The quantum similarity overlap is then used to optimize the mutual positions of the molecules. A comparison is made with TGSA, a topogeometrical approach, and the influence of differences on molecular clustering is discussed.