Iryanti Fatyasari Nata

Facile preparation of magnetic carbonaceous nanoparticles for Pb2+ ions removal

Magnetic carbonaceous nanoparticles were prepared by a facile two-step solution phase thermal synthesis. Magnetic nanoparticles (MNPs) with size less than 100 nm were first generated from FeCl(3) in a solvothermal reaction. The size could be significantly reduced to approximately 30 nm when 1,6-hexanediamine was employed in the reaction solution to functionalize the surface of MNPs with amine. Both the plain and amine-functionalized MNPs (MH) were effectively encapsulated in the carbonaceous shell by hydrothermal treatment in 0.5 M glucose solution. The saturation magnetization of MH decreased significantly from 70 to 25 emu/g after carbonaceous shell was formed. The as-prepared magnetic carbonaceous nanoparticles (MH@C) carries a negative surface charge (-30 mV) at neutral pH and has a point of zero charge (PZC) at pH 2. The carbonaceous shell not only can protect the magnetic nanoparticles (MNP) from the corrosive environment but also possesses a high adsorption capacity towards Pb(II). The adsorption isotherm at room temperature can be well-fitted by Langmuir model with a maximum adsorption capacity of 123 mg/g.

One-pot preparation of amine-rich magnetite/bacterial cellulose nanocomposite and its application for arsenate removal

Surface functionalization of bacterial cellulose (BC) nanofibrils with aminated magnetite nanoparticles (MH) was carried out by one-pot solvothermal reaction of 1,6-hexanediamine, FeCl3·6H2O and BC pellicle in ethylene glycol at 200 °C for 6 h. The presence of amine surface-functionalized magnetite nanoparticles on the surface of cellulose nanofibrils not only significantly enhanced the thermal and mechanical properties but also the amine content of the nanostructured bacterial cellulose pellicle. Approximately 10.5 mmol g−1 of amine was measured in the aminated magnetite-BC nanocomposite (BC@MH) which is about 14.3 fold higher than its counterpart (MH) prepared in the absence of BC pellicle. The never-dried BC@MH nanocomposite demonstrated a high adsorption capacity towards As(V) ions because of its high iron-oxide and amine content. Approximately 90 mg of As(V) can be adsorbed per gram of BC@MH.

Novel carbonaceous nanocomposite pellicle based on bacterial cellulose

A novel carbonaceous nanocomposite pellicle was prepared by one-step mild hydrothermal carbonization of bacterial cellulose pellicle soaked in glucose solution. The nano-fibrous structure of bacterial cellulose remains intact while carbonaceous spheres with nanometre sizes were generated from glucose during hydrothermal carbonization at 180 °C for 3 h. The carbonaceous spheres formed in situ and anchored on the nanofibers’ surface expanded the nanostructure of bacterial cellulose and the water-holding capacity decreased slightly from 98% to 93%. Approximately 80% w/w of the dried carbonaceous pellicle was found to be nanometre sized carbonaceous spheres. The size of carbonaceous spheres decreased significantly but had a 60% increase of surface carboxyl groups when the carbonaceous pellicle was prepared in the presence of acrylic acid. The carbonaceous spheres in the never-dried pellicle demonstrate a high adsorption capacity towards heavy metal ions. Approximately, 200 mg of Pb(II) and 1134 mg of Fe(III) can be adsorbed per gram of carbonaceous pellicle, respectively.

A chitin nanofibril reinforced multifunctional monolith poly(vinyl alcohol) cryogel

A highly porous and spongy monolith cryogel was prepared by a single freeze-thawing cycle of a PVA solution containing chitin nanofibrils (CNFs) as the nanofiller and glutaraldehyde (GA) as the cross-linker. The presence of CNFs significantly reinforced the spongy structure of the cryogel so that repeated squeezing-releasing did not deteriorate its spongy structure. The in situ self-polymerized polydopamine was formed inside the spongy cryogel by soaking the cryogel in a dopamine solution. The polydopamine modified cryogel (PVA-CNF-D) showed a very good antioxidant activity in that approximately 49% of free radicals of DPPH˙ was consumed within 2 min. Silver nanoparticles (SNPs) could be spontaneously reduced from silver nitrate solution and deposited onto the polydopamine modified surface without an exogenous reducing reagent. The SNP incorporated spongy cryogel demonstrated a very effective antibacterial activity against E. coli.

Facile microencapsulation of curcumin in acetylated starch microparticles

Abstract Highly acetylated starch was prepared by reacting corn starch with acetic anhydride. Acetylated starch (AS) is soluble in acetone and can be precipitated out from AS–acetone solution when deionised (DI) water is added as a non-solvent. The curcumin dissolved in AS–acetone solution could be effectively encapsulated in AS as spherical microparticles (1–3 μm) when mixed with the DI water. The encapsulation yield of curcumin could reach 96.3%. AS encapsulation not only resulted in five-fold lower UV degradation rate of curcumin, the free radical scavenging activity of curcumin still could be well maintained. Approximately, 40% of the 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH•) was consumed by curcumin encapsulated in AS microparticles within 2 min.

Facile Strategy for Surface Functionalization of Corn Cob to Biocarbon and Its Catalytic Performance on Banana Peel Starch Hydrolysis

The sulphonated biocarbon (C-SO 3 H) has been prepared from carbonization of corn cob and followed by one-step hydrothermal treatment. This research focus on characterization of C-SO 3 H and evaluate the capability of C-SO 3 H for hydrolyzed banana peel starch, and also investigate the optimum concentrations of substrate and the reaction time for hydrolysis. The C-SO 3 H was produced from corn cob (±60 mm mesh); it was carbonized at 400 °C for 1 hour. The resulting carbon was sulphonated by hydroxy ethyl sulphonic acid at 180 °C for 4 hours, and then washed with 50% methanol and water, and then resulting biocarbon was dried at 80 °C for 6 hour in oven. Based on Scanning Electron Microscopy (SEM) observation, structure morphology of corn cob was changed due to carbonization process. The C-SO 3 H after sulphonation has random pores with diameter around 3 µm–10 µm. The X-Ray Diffraction (XRD) showed increased of crystalline index of corn cob about 133% after carbonization. Analysis of EDX result for S component on C-SO 3 H is 3.79% w/w and capacity of H + is 1.447 mmol/g. The apparent peaks of -SO 3 H functional groups (1207 cm -1 and 1720 cm -1 ) on C-SO 3 H were indicated the by Fourier Transform Infra Red (FTIR). Optimum hydrolysis concentration of banana peel starch is 7% w/v for 60 min at 100 o C which Total Reducing Sugar (TRS) concentration about 0.688 mg/mL. Reusability of C-SO 3 H for 4 repeated used which showed a good performance that only 6% of decreasing activity of C-SO 3 H. The utilization of corn cob can be enhanced of corn cob and also it can be utilized as heterogeneous catalyst.

Biocomposite Materials of Eleocharis dulcis Fibers with Iron (III) Nanoparticles and Its Potential for Sasirangan Textile Wastewater Treatment

Eleocharis dulcis (Chinese water chesnut), locally Kalimantan named Purun Tikus, is a plant that grown in highly acidic swamps areas in South Kalimantan. Eleocharis dulcis (ED) , was usually used as material for traditional handicrafts. Therefore it is necessary for develop and innovate to convert the material becomes valuables. This research focus on the study of biocomposite nanoparticles of ED and its potentials as an adsorbent to reduce concentration of Pb 2+ ion, Total Suspended Solid (TSS) and color from Sasirangan textile industry wastewater. The synthesis of the biocomposite nanocomposite was made by solvothermal synthesis. Firstly, ED stemsdried was cutted to small size (250 micron), then through delignification process to eliminate lignin by 1% w/v NaOH solution. ED delignification put into hydrothermal reactor, right afterward was carried out by one-pot solvothermal reaction of 1,6-diaminohexane, iron (III) chloride hexahydrate, and ethylene glycol at 200 o C for 6 h.The process was produced two types of biocomposites, without the amino group (EDB-M) and the amino group (EDB-MH). The characterization results shown by SEM, magnetic nanoparticles have been formed on the surface of EDfiber.The ED biocomposite nanoparticles (EDB) with diameter size around 30–50 nm could be obtained. X-Ray Diffraction (XRD) analysis showed treatment of EDdelignification was increased the porosity of the fiber, shown by increased Crystalinity Index (CrI) about 72.75%. The biocomposites adsorbent, EDB-M and EDB-MH had adsorption capacity for Pb 2+ ions about 44.21 mg/g and 55.62 mg/g at equilibrium pH (pH e ) of 6 and equilibrium time of 2 hour. The effectiveness of reduced TSS was about of 91.9% and 98.1%. Beside that, the colour intensity of color was decreased about 96.7% and 97.8% for the EDB-M and EDB-MH, respectively.