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

Synthesis of nanosized of hydroxyapatite (HA) by electrochemical pulsed direct current (PDC) method has been studied The aim of this work is to study the influence of various PDC parameters (pH initial, electrode distance, duty cycle, frequency, and amplitude) on particle surface area of HA powders The electrochemical synthesis was prepared in solution Ca2+/EDTA4−/PO43+ at concentration 025/025/015 M for 24 h The electrochemical cell was consisted of two carbon rectangular electrodes connected to a function generator to produce PDC There were two treatments for particles after electrosynthesized, namely without aging and aged for 2 days at 40 °C For both cases, the particles were filtered and washed by demineralized water to eliminate the impurities and unreacted reactants Then, the particles were dried at 100 °C for 2 days The dried particles were characterized by X-ray diffraction, surface area analyzer, scanning electron microscopy (SEM), Fourier transform infrared spectra and thermogravimetr

/pdf/electrochemical-synthesis-of-nanosized-hydroxyapatite-by-4xisfolo6l.pdf

Electrochemical synthesis of nanosized hydroxyapatite by pulsed direct current method

In this research, a combination of hydrometallurgy and flame-assisted spray pyrolysis (FASP) to recycle and reproduce LiNi0.8Co0.15Al0.05O2 (NCA) waste is proposed. The NCA waste is obtained from a Li-ion battery facility. Valuable metals are extracted in 2 M nitric acid solution and 1.5 M of ecofriendly acetic acid, citric acid and maleic acid solutions and used as spray solution to produce NCA cathode material. The produced NCA powders were characterized by XRD, FTIR and SEM. XRD study shows the obtained NCA powders have layered structure with good ordering hexagonal layer. SEM images show the powders have agglomerated micro-sized particles. FTIR spectra analysis shows that NCA powders contain residual Li2CO3. The charge-discharge analysis demonstrates that produced NCA has a specific initial discharge capacity of 133 mAh/g and capacity retention of 87% after 200 cycles when cycled at the voltage range of 2.8 – 4.3 V and current density of 0.5C. The overall process is considered economical, practical and suitable for mass production.

Flame-assisted spray pyrolysis of lithium nickel cobalt aluminum oxide leaching stream

The use of Li-ion batteries has increased with the increasing of portable electronic media. Li-ion batteries have a life cycle hence a recycling process is needed in order to reduce the potential hazard of waste while increasing the economic value of unused battery material, especially its cathode active material. This study used Lithium Nickel Cobalt Oxide (NCA) cathode scrap to be regenerated which NCA material has high energy density and high capacity. The pretreatment process is one of the determinants in the subsequent recycling process. In this study, the effect of heating on the pretreatment process was carried out with variation temperatures of 500-800 0 C to obtain powder which will be recycled. The combination process of the leaching and co-precipitation was used to regenerate the cathode active material. Atomic Absorption Spectrophotometry (AAS) was performed to determine leaching efficiency using 4M H 2 SO 4 at 40 0 C for 3 hours. X-ray Diffraction (XRD) analysis showed that NCA material has been successfully regenerated which the diffraction peaks of NCA material was in accordance with JCPDS standards. The morphology of NCA material was tested using Scanning Electron Microscopy (SEM). Electrochemical testing uses a cylindrical battery at 2.7-4.2 Volt which the initial specific discharge capacity of the power is 62.13 mAh / g.

/pdf/effect-of-heating-on-the-pretreatment-process-for-recycling-hpcf6ch7ax.pdf

Effect of Heating on the Pretreatment Process for Recycling Li-Ion Battery Cathode

This research designed of documentation management system laboratory for Mechatronics Laboratory based on SNI ISO/IEC 17025:2008 refers to documentation management system laboratory in UPT Integrated Laboratory. Mechatronics laboratory is expanding the scope of the UPT Integrated Laboratory. Design of documentation management system laboratory required to obtain accreditation from KAN. Documents were designed consisting of level 1 Quality Guidelines, level 2 Procedures, level 3 Work Instrictions, and level 4 Forms. Design of the documents were done with five stages document requirements identification, business process identification, analysis the availability of the necessary documents, designing documents, and documents verification. From the stages, are known that 10 documents level 1 need adjustments, 2 documents level 3 and 11 documents level 4 need to be designed. On documents verification, it is known that there are documents that requires improvements in the format and content. If Mechatronics Laboratory develop, then required adjustments to the documents

/pdf/perancangan-dokumentasi-sistem-manajemen-pada-laboratorium-4y3wce015w.pdf

Perancangan Dokumentasi Sistem Manajemen pada Laboratorium Mekatronika UNS Berdasarkan SNI ISO/IEC 17025 : 2008

Fuel grade bioethanol preparation from talas (colocasia esculenta L) flour needs 
some steps. First, polysaccharide in talas flour is converted to monosaccharide (glucose) in 
hydrolysis process. The next step is fermentation that glucose is converted to ethanol by 
Sacharomyces cereviceae yeast. The final of steps is distillation and adsorption methods 
that ethanol is concentrated and dried to get min 99 % ethanol. The objectives of the 
researches using talas flour as source of alternative energy are to increase economic value 
of talas and to decrease using fossil energy. The aims of this research were to find the effect 
of α-amilase and glucoamilase concentrate to glucose results in hydrolyze reaction, to find 
the optimum condition of fermentation using Saccharomyces cereviceae yeast, and to study 
ethanol purification in distillation and adsorption method with CaO. Hydrolysis was carried 
out in three necked bottle with mantle heater equipped stirrer and reflux condenser. 
Fermentation process was done with simple fermentation. Purification of ethanol was done 
with distillation method that used packed column and reflux condenser and adsorption 
method that used CaO as adsorbent and column filled. The result of this research was every 
1 L ethanol that was 99.4 % concentrate ethanol needs 8.7 kg talas, 3 g α-amilase and 8 g 
glucoamilase, and 4.4 g dried Saccharomyces cerevisiace yeast. The cost of preparation 
ethanol was Rp 6,625.00/L. 
Keywords : bioethanol, Sacharomyces cereviceae, talas flour

/pdf/bioetanol-fuel-grade-dari-talas-colocasia-esculenta-2y84ibxgpd.pdf

Adrian Nur

Papers

Electrochemical synthesis of nanosized hydroxyapatite by pulsed direct current method

Flame-assisted spray pyrolysis of lithium nickel cobalt aluminum oxide leaching stream

Effect of Heating on the Pretreatment Process for Recycling Li-Ion Battery Cathode

Perancangan Dokumentasi Sistem Manajemen pada Laboratorium Mekatronika UNS Berdasarkan SNI ISO/IEC 17025 : 2008

BIOETANOL FUEL GRADE DARI TALAS (Colocasia Esculenta)