Magnetic iron oxides were prepared by precipitation of Fe(II) hydroxide using different precipitation agents: ammonia, benzylamine and sodium hydroxide, followed by oxidation with the oxygen dissolved in water. Thermal analysis, coupled with FTIR spectroscopy, has evidenced the formation of a mixture of magnetite and maghemite, with a higher content of magnetite in case of the powder synthesized with benzylamine. The stability of magnetite at oxidation by air during storage at room temperature and 60 °C was investigated by means of TG/DSC simultaneous thermal analysis, FTIR spectroscopy and X-ray diffractometry. Thermal analysis evidenced an exothermic process with mass gain in temperature range 100–190 °C, corresponding to magnetite oxidation process, but due to the superposition of other processes it could not offer quantitative information. FTIR spectroscopy has provided, especially through the first and second derivatives of FTIR spectra, the most valuable information regarding the evolution of magnetite to maghemite, due to their different characteristic bands. XRD technique has evidenced a slight shift of the main diffraction peaks at higher 2-theta values during the evolution of magnetite to maghemite. According to thermal analysis data, the powder synthesized with ammonia was completely oxidized after 15 days, while the other two powders, synthesized with benzylamine and sodium hydroxide, were completely oxidized after 110 days of keeping in air at room temperature. For a temperature of 60 °C, the oxidation was much faster; the oxidation process of the powder synthesized with benzylamine disappeared from TG/DSC curves after 1 day. All final powders were formed from nanoparticles with diameters up to 25 nm, with magnetic properties characteristic to nanometric maghemite.

Investigation of magnetite nanoparticles stability in air by thermal analysis and FTIR spectroscopy

Recent advances in the methanol carbonylation reaction into acetic acid

The disposal of hazardous waste of any form has become a great concern for the industrial sector due to increased environmental awareness. The increase in usage of hydroprocessing catalysts by petrochemical industries and lithium-ion batteries (LIBs) in portable electronics and electric vehicles will soon generate a large amount of scrap and create significant environmental problems. Like general electronic wastes, spent catalysts and LIBs are currently discarded in municipal solid waste and disposed of in landfills in the absence of policy and feasible technology to drive alternatives. Such inactive catalyst materials and spent LIBs not only contain not only hazardous heavy metals but also toxic and carcinogenic chemicals. Besides polluting the environment, these systems (spent catalysts and LIBs) contain valuable metals such as Ni, Mo, Co, Li, Mn, Rh, Pt, and Pd. Therefore, the extraction and recovery of these valuable metals has significant importance. In this Review, we have summarized the strategies used to recover valuable (expensive) as well as cheap metals from secondary resources-especially spent catalysts and LIBs. The first section contains the background and sources of LIBs and catalyst scraps with their current recycling status, followed by a brief explanation of metal recovery methods such as pyrometallurgy, hydrometallurgy, and biometallurgy. The recent advances achieved in these methods are critically summarized. Thus, the Review provides a guide for the selection of adequate methods for metal recovery and future opportunities for the repurposing of recovered materials.

/pdf/recycle-recover-and-repurpose-strategy-of-spent-li-ion-22ggr5h40r.pdf

Recycle, Recover and Repurpose Strategy of Spent Li-ion Batteries and Catalysts: Current Status and Future Opportunities

Three different novel chitosan derivatives for medical or biotechnological applications have been successfully obtained by chemical modification of reactive amino and hydroxyl groups in chitosan chain. The modification has led to incorporation of different amount (one to three) of long-distanced amino and imine groups into each repeating unit. These highly functionalized chitosan derivatives were used as a matrix for magnetite nanoparticles. The thermal stability of all obtained chitosan materials has been determined using thermogravimetric analysis in oxidative and inert atmosphere. Chitosan containing two side substituents behaves differently from the other two, which is caused by the significant water uptake. Magnetite causes decrease in thermal stability of studied chitosan derivatives. The highest stability is observed for the nanocomposite obtained from chitosan with three side groups. The changes in the structure of the magnetite core have been observed above 600 °C in nitrogen. Due to the different competitive reactions occurring in the modified chitosan, the proposed mechanism of thermal degradation is very complex.

/pdf/effect-of-side-substituents-on-thermal-stability-of-the-m8sak5xvap.pdf

Effect of side substituents on thermal stability of the modified chitosan and its nanocomposites with magnetite

Structural and magnetic
studies of monophasic maghemite (γ-Fe2O3)
magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical
route are reported in this paper. For the synthesis, a starting precursor of
magnetite (Fe3O4)
in basic medium was oxidized at room temperature by adjusting the pH = 3.5
at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD)
pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms
only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates
the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement
(6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to
complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken
at different temperatures show almost zero coercivity and remanence indicating
superparamagnetic domain and high magnetic saturation.

/pdf/structural-and-magnetic-properties-of-monophasic-maghemite-g-45vzab9tfd.pdf

Structural and Magnetic Properties of Monophasic Maghemite (γ-Fe2O3) Nanocrystalline Powder

Ethanol was used as carbon source in the synthesis of arbon nanotubes (CNT) by chemical vapor deposition (CVD) over Fe/Co catalyst. The product was evaluated using transmission electron microscopy (TEM). Branching structures of multi-walled carbon nanotubes (MCNTs) with diameters of arou d 50 nm were observed on the TEM micrographs. The influence of reaction variable such as temperature and time reaction was also studied. Carbon nanotubes are formed at 9000C after 15 and 20 min. The reaction mechanism was then scussed in this paper.

/pdf/sintesis-karbon-nanotube-dari-etanol-dengan-metode-chemical-15exuxllzd.pdf

Sintesis karbon nanotube dari etanol dengan metode chemical vapor deposition

ZnO nanoparticles have interesting characteristics and potential applications in various lines of life. However, its size and weak compatibility can cause aggregation. Therefore, ZnO nanoparticles are composited with silica aerogel as a buffer matrix to enhance the potential function of ZnO to form ZnO/silica aerogel nanocomposites. The nanocomposite was synthesized using the molten salt method by involving the main precursor ZnCl2 which was calcined at 450 °C together with a silica aerogel buffer matrix in various calcination time variations. The success of synthesis based on FT-IR analysis is shown by the presence of vibration groups of silanol (Si-OH), siloxane (Si-O-Si), and Zn-O vibrations from the ZnO lattice. The inclusion of ZnO nanoparticles in the silica aerogel matrix is indicated by the presence of a peak in the XRD test that relates to ZnO standard peak (JCPDS No.36-1451). The analysis results based on X-Ray Fluorescence showed that the optimum percentage of ZnO formation in the silica matrix occurred at 40 minutes of calcination time. Mapping of the synthesized results showed the presence of ZnO nanoparticles scattered on the silica aerogel matrix. ZnO nanoparticles experienced a fairly homogeneous distribution on the silica aerogel matrix with 70% of Zn composited with the size of the nanocomposite particles produced ranging from 25-72 nm. 

Synthesis and characterization of ZnO/silica aerogel nanocomposites

Two facts, namely the industrial development in various fields and limited natural dyes, have led to an increase of synthetic dyes uses which have the potential to produce hazardous wastes if not managed properly. Some efforts to process liquid waste, especially synthetic dye waste can be done in many ways. A simple but supposedly effective way is to utilize magnetic nanoscale adsorbent material as a waste processing agent. The purpose of this study was to synthesize salicylic acid-modified magnetite nanoparticles and apply them as a liquid waste processor, especially Malachite Green waste. Malachite Green is a dye that is often used in the industry. The magnetic properties possessed by magnetite material are beneficial in material recovery. The main stages of the study include the synthesis of magnetite nanoparticles by electro-oxidation of iron in water; modification of material with salicylic acid; characterization of synthesized materials with XRD, FTIR, SEM, and BET; and Malachite Green waste treatment process by salicylic acid-modified magnetite. The results of XRD, FTIR, and SEM characterization showed that the salicylic acid-modified magnetite nanoparticles were successfully synthesized. The results of BET characterization provide a particle surface area of 88 m2/g which shows the potential of the material as an adsorbent. The application of the material as an adsorbent successfully absorbed 88% Malachite Green with an adsorption capacity of 15.5 mg/g at room temperature in 120 minutes.

Synthesis of salicylic acid modified magnetite nanoparticles and its application in wastewater treatment

Scaling-up the Production Process of Lithium Nickel Manganese Cobalt Oxide (NMC)

Sekolah Menengah Kejuruan (SMK) Muhammadiyah 4 Surakarta memiliki jurusan Kimia Industri yang mempersiapkan tenaga terampil di industri kimia untuk mendukung dalam pengembangan teknologi. Salah satu Industri Kimia yang berkembang saat ini adalah Industri Baterai Lithium Ion (LIB). LIB saat ini digunakan tidak hanya pada perangkat elektronik portabel, seperti komputer dan telepon seluler, tetapi juga untuk kendaraan listrik atau kendaraan hybrid. Oleh karena itu, lulusan SMK dengan Program Keahlian Kimia Industri hendaknya menyiapkan lulusan yang mempunyai kompetensi di bidang teknologi baterai. Dengan kompetensi dosen dalam teknologi produksi material aktif baterai pada skala mini plant dan fasilitas yang mewadai di Pusat Unggulan IPTEK (PUI) PT Teknologi Penyimpanan Energi Listrik, maka sangat memungkinkan dosen untuk mengenalkannya kepada siswa SMK Muhammadiyah 4 Surakarta. Metode yang dilakukan dalam pelatihan ini adalah metode ceramah, diskusi dan praktik. Adapun materi yang disampaikan mengenai baterai lithium ion (aplikasi, jenis, tipe, struktur, proses pembuatan material aktif, dan fabrikasi). Kegiatan praktik yang dilakukan yaitu praktik pembuatan material aktif katoda dengan metode ko-presipitasi dan fabrikasi sel baterai. Hasil kegiatan ini adalah kompetensi siswa dan guru meningkat yang ditunjukkan dengan nilai Pre-Test yang lebih baik dibandingkan dengan Post-Test.

Adrian Nur

Papers

Sintesis karbon nanotube dari etanol dengan metode chemical vapor deposition

Synthesis and characterization of ZnO/silica aerogel nanocomposites

Synthesis of salicylic acid modified magnetite nanoparticles and its application in wastewater treatment

Scaling-up the Production Process of Lithium Nickel Manganese Cobalt Oxide (NMC)

Peningkatan Kompetensi Siswa SMK Muhammadiyah 4 Surakarta mengenai Industri Baterai Lithium Ion