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The high application of Poly(styrene-maleic acid) (PSMA) in an aqueous environment, such as biomedical purposes, makes the interaction between PSMA and water molecules interesting to be investigated. This study evaluated the conformation, the hydrogen bond network, and the stabilities of all the possible intermolecular interactions between PSMA with water (PSMA−(H2O)n, n = 1–5). All calculations were executed using the density functional theory (DFT) method at B3LYP functional and the 6–311G** basis set. The energy interaction of PSMA–(H2O)5 complex was –56.66 kcal/mol, which is classified as high hydrogen bond interaction. The Highest Occupied Molecular Orbital (HOMO) – Lowest Unoccupied Molecular Orbital (LUMO) energy gap decreased with the rise in the number of H2O molecules, representing a more reactive complex. The strongest hydrogen bonding in PSMA–(H2O)5 wasformed through the interaction on O72···O17–H49 with stabilizing energy of 50.32 kcal/mol, that analyzed by natural bond orbital (NBO) theory. The quantum theory atoms in molecules (QTAIM) analysis showed that the hydrogen bonding (EHB) value on O72···O17–H49 was –14.95 kcal/mol. All computational data revealed that PSMA had moderate to high interaction with water molecules that indicated the water molecules were easily transported and kept in the PSMA matrix.

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Abstract5‐Hydroxymethyl furfural (HMF) obtained from biomass can be converted to 2,5‐diformylfuran (DFF), a valuable chemical intermediate. However, the typical HMF oxidation process requires energy consumption such as high temperature and oxygen pressure. Herein, Au2S decorated CdS nanowires (denoted as Au2S@CdS NWs) are fabricated by a simple ion exchange method and applied as a heterostructure photocatalyst system for HMF oxidation under mild conditions. Under visible light irradiation, the photocatalytic performance of Au2S@CdS NWs is significantly enhanced compared with pristine CdS NWs, in which Au2S (0.25%)@CdS NWs achieve the high DFF yield (≈95%) for 4 h reaction time. This result means that the heterogeneous interface formed between CdS NWs and Au2S promotes the separation efficiency of photogenerated charges, which leads to high catalytic activity. Moreover, Au2S (0.25%)@CdS NWs work well for HMF conversion to DFF under anaerobic and aerobic conditions. Control experiments and characterization are conducted to investigate each reaction mechanism. Consequently, it is found that the photogenerated hole directly oxidizes HMF to DFF under anaerobic conditions and the 1O2 produced from oxygen is the active species for HMF conversion to DFF under aerobic conditions.

Melalui reaksi taut silang antara kitosan dan asam sitrat, membran kitosanasam sitrat (CC) disiapkan sebagai katalis heterogen dalam proses produksi biodiesel dari minyak kelapa sawit dan metanol. Sifat membran CC dianalisis secara fisikokimia dan menggunakan spektroskopi FTIR dan TGA. Berdasar data fisikokimia, didapatkan bahwa masuknya gugus TPP dalam rangka kitosan berkorelasi dengan peningkatan porositas, hidrofilisitas, serapan air, dan fluks membran. Sisi katalitik dari membran CC pada proses produksi biodiesel dipelajari pada beberapa kondisi konversi. Didapatkan bahwa konversi minyak kelapa sawit mencapai 98,4% dengan kondisi waktu reaksi 75 menit, suhu 70 oC, rasio mol minyak/metanol 1:3 dan jumlah katalis sebesar 70 mg.

High concentrations of creatinine and urea in the blood can be removed by dialysis using semipermeable membranes that are selective for certain species and hold other species through diffusion processes. This ability requires a membrane that has an active side, which functions as a targeted species identifier. The membrane must be biocompatible because the membrane will be in direct contact with the body’s biological systems. The membrane material that is made must be acceptable to the blood system so that there is no rejection from the body and have a large contact area to obtain an effective diffusion process. For this reason, a hollow fiber membrane (HFM) is needed. One of the synthetic polymers used as the base material for HFM is PSf. PSf has mechanical strength, heat resistance, and is easily formed into HFM. However, PSf has disadvantages such as lack of active side and less compatible with blood due to its hydrophobic properties. Modification using PEG and chitosan will reduce the hydrophobicity of the PSf. Membrane results were analyzed the physical, chemical, and transportability for urea and creatinine. The results of functional group characterization by FTIR show that the modification reaction was successfully carried out on polysulfone to produce PEG-PSf/CS. The modification succeeded in making the PSf membrane more hydrophilic, as evidenced by a decrease in the contact angle from 69.4° (PSf) to 53° (PEG-PSf/CS). Water uptake capability increases to 609%, and membrane porosity increases porosity increased from 72 to 83%. The water flux is also increased. Creatinine clearance ability increases from 0.09 mg/dl to 0.25 mg/dL. Urea clearance ability increases from 2.3 mg/dL to 3.07 mg/dL. The SEM image showed that the modification makes the membranes more porous.

The abundance of applications of alginates in aqueous surroundings created by their interactions with water is a fascinating area of research. In this paper, computational analysis was used to evaluate the conformation, hydrogen bond network, and stabilities for putative intermolecular interactions between alginate dimers and water molecules. Two structural forms of alginate (alginic acid, alg, and sodium alginate, SA) were evaluated for their interactions with water molecules. The density functional theory (DFT-D3) method at the B3LYP functional and the basis set 6-31++G** was chosen for calculating the data. Hydrogen bonds were formed in the Alg-(H2O)n complexes, while the SA-(H2O)n complexes showed an increase in Van der Walls interactions and hydrogen bonds. Moreover, in the SA-(H2O)n complexes, metal-nonmetal bonds existed between the sodium atom in SA and the oxygen atom in water (Na…O). All computational data in this study demonstrated that alginate dimers and water molecules had moderate to high levels of interaction, giving more stability to their complex structure.