Metformin adsorption onto activated carbons prepared by hydrothermal carbonization and activation

The hydrothermal carbonization can be considered an environmental friendly process for the production of carbon materials with tailored properties, such as regular porous structure and specific surface chemistry. This process is easy to perform and uses mild temperatures without the use of solvents or gases, which results in a positive environmental balance when compared with the usual pyrolysis process [1]. Diabetes affects more than 152 million people in Europe and is on the rise all over the World. Metformin is one of the most used drugs to treat type 2 diabetes. This drug is an endocrine disruptor with a potential negative impact in the environment due to the fact that metformin is almost not metabolized in the human body and the incorrect disposal into the domestic garbage. Another relevant aspect is the danger of overdose intake of the drug that can lead to lactic acidosis, which in extreme cases can be lethal. The work now reported study the in vitro adsorption of metformin onto activated carbons using simulated gastric and intestinal fluids

Molecularly imprinted surfaces using surface-bound templates

The invention claimed is: 1. A method of producing a hierarchical molecularly-imprinted material, comprising: (a) synthesizing at least one peptide corresponding to an epitope of a target peptide or target protein by attaching a first amino acid to modified surfaces of the pores of a disposable surface-modified porous support, followed by attaching one or more amino acids to said first amino acid to produce said at least one peptide attached to said surfaces; (b) providing a selected monomer mixture; (c) contacting said monomer mixture with said support surface-attached peptide so that the monomer mixture enters the pores of the porous support; (d) initiating polymerisation or at least one crosslinking reaction of said monomer mixture to yield a polymer; and (e) dissolving or degrading said at least one support surface-attached peptide and said support; to provide a polymer material comprising a hierarchical molecular imprint of the epitope synthesized in step (a) and the porous support, wherein the epitope is a peptide that corresponds to only part of the target peptide or protein. 2. A method according to claim 1, wherein said target peptide is a dipeptide or oligopeptide. 3. A method according to claim 1, wherein step (d) is conducted with the aid of at least one factor consisting of crosslinking agents, heat, and ultraviolet irradiation. 4. A method according to claim 1, wherein said epitope of a target peptide is selected from the group consisting of FMOC-Phe-Gly-Si, H-Phe-Gly-Si, FMOC-Phe-Gly-OH, H-Phe-Gly-NH.sub.2, H-Phe-Gly-Gly-Phe-OH (SEQ ID NO:1), and H-Gly-Phe-OH. 5. A method according to claim 1, wherein said disposable surface modified support is modified silica or controlled pore glass (CPG). 6. A method according to claim 1, wherein said monomer mixture comprises monomers selected from the group consisting of styrene/divinyl benzene, methacrylates, acrylates, acrylamides, methacrylamides and combinations thereof. 7. A method of using a molecularly-imprinted material, comprising: producing a molecularly-imprinted material according to claim 1; and using said molecularly-imprinted material as an affinity phase for the separation of biological macromolecules or oligomers. 8. A method according to claim 7, wherein said biological macromolecules or oligomers are selected from the group consisting of peptides, polypeptides, oligopeptides, proteins, nucleic acids, oligonucleotides, polynucleotides, saccharides, oligosaccharides, and polysaccharides. 9. A chromatographic stationary phase, comprising a molecularly imprinted material produced according to claim 1, wherein said peptide, oligosaccharide or oligonucleotide of step (c) is selected from the group consisting of FMOC-Phe-Gly-Si, H-Phe-Gly-Si, FMOC-Phe-Gly-OH, H-Phe-Gly-NH.sub.2, H-Phe-Gly-Gly-Phe-OH (SEQ ID NO:1), and H-Gly-Phe-OH

Surface interactions during the removal of emerging contaminants by hydrochar-based adsorbents

Funding: The work was partially funded by the FCT (Grant FRH/BD/82696/2011) with National (OE) and European Union (FEDER, program COMPETE of QREN) funds. The authors are also grateful to Junta de Extremadura and FEDER (Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa”), for financial help by project IB16108, and also to the program “Ayudas a grupos de la Junta de Extremadura” GR18150. Acknowledgments: The authors are grateful for the SAIUEX (Servicios de Apoyo a la Investigación de la Universidad de Extremadura) for their help in textural and surface chemistry analysis of the hydrochars.The aim of this work was to test activated carbons derived from hydrochars produced from sunflower stem, olive stone and walnut shells, as adsorbents for emerging contaminants in aqueous solution, namely fluoxetine and nicotinic acid. The adsorption capacity was determined by the chemical nature of the adsorbents, namely the presence of specific functional groups and their positive or negative ionization in aqueous solutions and also by steric factors. The activated carbons produced by air showed a higher adsorption capacity of fluoxetine, whilst the samples produced by carbon dioxide activation were more useful to remove nicotinic acid. In general, surface acidity was advantageous for fluoxetine adsorption and detrimental for nicotinic acid removal. The adsorption mechanisms involved in each case were discussed and related to the adsorbents characteristics. The maximum adsorption capacity, Q0, given by the Langmuir model was 44.1 and 91.9 mg g-1 for fluoxetine and nicotinic acid adsorption, respectively.publishersversionpublishe

Influence of hydrothermal pretreatment on the pyrolysis of spent grains

Hydrothermal carbonization process (HTC) is a thermochemical process which operates at elevated temperature and pressure, where liquid water is used as a reaction medium [1]. The biomass is converted into a lignite-like solid product called hydrochar [2]. The advantage of hydrothermal treatment is a possibility to convert high moist bio-waste streams without thermal drying. A two-step carbonization process (Figure 5) consisting of HTC and pyrolysis may improve the properties of final biochar (e.g., carbon content, surface area, and electrical conductivity). Hydrothermal conversion occurs using different mechanisms (e.g., hydrolysis and polymerization of intermediates) compared to pyrolysis, due to the liquid water environment, which also improves the heat transfer across the particles [1,3]. Hydrochar can be easily mechanically dewatered, due to higher hydrophobicity than the initial feedstock [2]. The mass of initial biomass is also reduced according to the HTC yield, which results in a lower mass flow of material for pyrolysis reactor and previous drying step. The two-step carbonization concept may spread the range of feedstocks used for biochar production and improve the overall energy efficiency as well as economic feasibility of pyrolysis, using wet biomass streams. Please click Additional Files below to see the full abstract

Electrochemical behaviour of activated carbons obtained via hydrothermal carbonization

Activated carbons were prepared by chemical activation of hydrochars, obtained by hydrothermal carbonisation (HTC) using low cost and abundant precursors such as rye straw and cellulose, with KOH. Hydrochars derived from rye straw were chemically activated using different KOH/precursor ratios, in order to assess the effect of this parameter on their electrochemical behaviour. In the case of cellulose, the influence of the hydrothermal carbonisation temperature was studied by fixing the activating agent/cellulose ratio. Furthermore, N-doped activated carbons were synthesised by KOH activation of hydrochars prepared by HTC from a mixture of glucose with melamine or glucosamine. In this way, N-doped activated carbons were prepared in order to evaluate the influence of nitrogen groups on their electrochemical behaviour in acidic medium. The results showed that parameters such as chemical activation or carbonisation temperature clearly affect the capacitance, since these parameters play a key role in the textural properties of activated carbons. Finally, symmetric capacitors based on activated carbon and N-doped activated carbon were tested at 1.3 V in a two-electrode cell configuration and the results revealed that N-groups improved the capacitance at high current density.The authors thank the Spanish MINECO, GV and FEDER (PROMETEOII/2014/010, Projects CTQ2012-31762 and MAT2013-42007-P) and D.S.T. is indebted to MINECO for a predoctoral FPI grant (BES-2010-035238). M. Titirici, Li Zhao and Linghui Yu would like to acknowledge financial support from the Max-Planck Society. Li Zhao is grateful to China Scholarship Council for awarding her a PhD fellowship in Germany

Tailoring the porosity of chemically activated hydrothermal carbons: Influence of the precursor and hydrothermal carbonization temperature

Advanced porous materials with tailored porosity (extremely high development of microporosity together with a narrow micropore size distribution (MPSD)) are required in energy and environmental related applications. Lignocellulosic biomass derived HTC carbons are good precursors for the synthesis of activated carbons (ACs) via KOH chemical activation. However, more research is needed in order to tailor the microporosity for those specific applications. In the present work, the influence of the precursor and HTC temperature on the porous properties of the resulting ACs is analyzed, remarking that, regardless of the precursor, highly microporous ACs could be generated. The HTC temperature was found to be an extremely influential parameter affecting the porosity development and the MPSD of the ACs. Tuning of the MPSD of the ACs was achieved by modification of the HTC temperature. Promising preliminary results in gas storage (i.e. CO2 capture and high pressure CH4 storage) were obtained with these materials, showing the effectiveness of this synthesis strategy in converting a low value lignocellulosic biomass into a functional carbon material with high performance in gas storage applications.MMT and CF would like to thank the Max-Planck Society for financial support. DLC, DST, JPML and DCA would like to thank the Spanish MINECO, Generalitat Valenciana and FEDER (Projects CTQ2012-31762 and PROMETEO/2009/047) for financial support. DST. thanks MICCIN (BES-2010-035238)