فیلترها/جستجو در نتایج    

فیلترها

سال

بانک‌ها



گروه تخصصی




متن کامل


نویسندگان: 

MOHAMMADKHANI M. | ABDOLLAHY M. | KHALESI M.R.

اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    11
  • شماره: 

    3
  • صفحات: 

    921-933
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    132
  • دانلود: 

    0
چکیده: 

Copper oxide minerals such as malachite do not respond well to the traditional copper sulfide collectors, and require alternative flotation schemes. In many copper ore mines, significant copper oxide minerals, especially malachite, are associated with sulfide minerals. Considering that Xanthates are most widely used in the flotation of sulfide minerals as well as copper sulfide minerals and, hydroxamate has shown a good selectivity for copper oxide minerals. Use of the synergistic effect of Xanthate and hydroxamate can be an effective way to increase the flotation efficiency of copper oxide minerals along with sulfide minerals. In this work, we investigate the individual interactions of potassium amyl Xanthate (PAX) and potassium alkyl hydroxamate (HXM) with the natural malachite and explore their synergistic effects on the malachite flotation. The results of solubility of malachite in collector solutions, changes in the malachite surface potential, adsorption kinetics, adsorption densities, dynamic contact angles, FT-IR analyses, and small-scale flotations, are discussed. The results obtained demonstrate that PAX and HXM are chemically co-adsorbed on the malachite surface, and the amount of PAX adsorbed on the malachite surface is considerably increased in the mixed PAX/HXM systems because of the co-adsorption mechanism. The flotation results confirm that the mixed PAX/HXM exhibit a superior flotation performance of malachite compared to the individual system of PAX or HXM. Based on these results, the mixed PAX/HXM exhibit a remarkable synergism effect on malachite surface hydrophobicity.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 132

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
نویسندگان: 

NEDJAR ZOHIR | BARKAT DJAMEL

اطلاعات دوره: 
  • سال: 

    2012
  • دوره: 

    9
  • شماره: 

    5
  • صفحات: 

    709-714
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    310
  • دانلود: 

    0
چکیده: 

The effect of sulfite interaction with galena on the mechanism of potassium isoamyl Xanthate (KIAX) synthesized adsorption onto galena surfaces has been studied in situ using electrochemical potential; FTIR spectra and SEM have been used to identify the mechanism of interaction between sulfite and galena surfaces. Activated galena with copper sulfate (10-4 M) has been investigated at pH 9.12 and potassium isoamyl Xanthate (3×10-3 M) concentration. Oxidised galena surfaces have relatively low concentration of adsorbed Xanthate and high potential (Eopt=-89 mV); adsorbed colloidal (Pb-IAX, 1,123.08 cm-1) is found even at high Xanthate concentration, colloidal lead oxide/hydroxide particles have been imaged after 10-4M lead sulfate addition at pH 9.12. The behavior of this system is consistent with ion exchange between Xanthate and hydroxide followed by oxidation to dixanthogen (X2, 1,273.56 cm-1) and diffusion of this species across the surface.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 310

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
نویسندگان: 

PALATY S. | JOSEPH R.

نشریه: 

Iranian Polymer Journal

اطلاعات دوره: 
  • سال: 

    2004
  • دوره: 

    13
  • شماره: 

    2
  • صفحات: 

    85-91
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    393
  • دانلود: 

    0
چکیده: 

Zinc salts of ethyl, isopropyl and butyl Xanthates were prepared in the laboratory. The effect of these Xanthates with zinc diethyldithiocarbamate (ZDC) on the vulcanization of HAF filled NR compound has been studied at different temperatures. The rubber compounds with the three Xanthate accelerators and ZDC were cured at various temperatures from 60°C–150°C. The sheets were moulded and properties such as tensile strength, tear strength, cross-link density, elongation-at-break, compression set, heat build up, abrasion resistance, flex resistance etc. were evaluated. The properties showed that zinc Xanthate/ZDC accelerator combination has positive synergistic effect on the mechanical properties of NR compounds. The curing of HAF filled NR compound containing zinc Xanthate/ZDC is slightly slower than the curing of the corresponding gum compounds. It is seen that, by gradually increasing the amount of the accelerator, the cure time of black filled NR compound can be made equal to that of the gum compound.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 393

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
نویسندگان: 

NEDJAR Z. | BARKAT D.

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    10
  • شماره: 

    4
  • صفحات: 

    55-64
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    370
  • دانلود: 

    0
چکیده: 

In this study, we suggest proceeding to an experimental study concerning the synthesis of new organo metallic product Xanthate (KIBX) by intermittent method and their use in the processes of sulphides flotation.The adsorption of potassium isobutyl Xanthate (KIBX 3⋅10-3M) on sphalerite has been studied using electrochemical potential, FTIR technique and SEM. Non activated minerals and minerals activated with copper sulfate (10-4 M) and copper nitrate (10-4 M) have been investigated at pH 7.5. Surface species have been identified by FTIR and correlated with SEM. After copper sulfate activation, copper Xanthate exists on all of the minerals studied.Neutral pH is the most suitable for potassium isobutyl Xanthate adsorption on sphalerite.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 370

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
اطلاعات دوره: 
  • سال: 

    2025
  • دوره: 

    11
  • شماره: 

    3
  • صفحات: 

    1035-1056
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    4
  • دانلود: 

    0
چکیده: 

BACKGROUND AND OBJECTIVES: The increase in industrial effluent discharges from sectors such as smelting, electroplating, pharmaceuticals, and ceramics has led to a rise in heavy metal presence in ecosystems, posing a growing environmental risk. In the search for increasingly efficient materials, there has been growing interest in using adsorbents derived from both biological sources and industrial waste, due to their low cost, availability, and effectiveness in removing heavy metals from aqueous environments. The objective of this study was to assess the potential of a modified adsorbent resin, synthesized from mineral coal waste originating in Cesar, Colombia, for the removal of cadmium and lead from aqueous solutions as a sustainable remediation strategy.METHODS: The coal waste was chemically modified using sodium hydroxide and carbon disulfide to synthesize the adsorbent resin. Batch adsorption experiments were conducted at potential of hydrogen levels ranging from 3 to 8 to evaluate the removal performance. The influence of potential of hydrogen on adsorption efficiency was investigated, and the experimental data were subjected to a comparative modeling approach. Adsorption equilibrium was assessed using the Freundlich, Langmuir, and Langmuir–Freundlich isotherms, while kinetic behavior was interpreted through pseudo-first- and second-order models.FINDINGS: The results demonstrated that the removal efficiencies varied with potential of hydrogen, reaching maximum values when it was adjusted to 6, with 98 percent for lead and 97 percent for cadmium. The adsorption process followed the Freundlich isotherm, suggesting a multilayer adsorption mechanism, and the pseudo-second-order kinetics indicated that chemisorption was the dominant mechanism.CONCLUSION: This study highlighted the potential of modified mineral coal waste as an effective adsorbent for the removal of cadmium and lead, offering a promising alternative for the treatment of industrial wastewater. In addition to its high performance, this strategy contributes to the valorization of solid waste from coal mining, promoting a circular economy and reducing the environmental impact associated with its disposal.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 4

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
نویسندگان: 

Rafiei Hamid | ABBASIAN MOJTABA | YEGANI REZA

نشریه: 

Iranian Polymer Journal

اطلاعات دوره: 
  • سال: 

    2020
  • دوره: 

    29
  • شماره: 

    5
  • صفحات: 

    371-381
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    50
  • دانلود: 

    0
چکیده: 

For the first time formation of well-defined poly n-vinylpyrrolidone/n-TiO2 nanocomposite by Xanthate-mediated radical polymerization was accomplished. The synthesis of polymer nanocomposite materials has been intensively studied due to their extraordinary properties and wide-spread potential applications. For this purpose, first 2‐, propionic acid-O-ethyl Xanthate, as a RAFT agent, was synthesized by the reaction of 2-bromopropionic acid with potassium O-ethyl Xanthate with acetone as the solvent. A carboxylic group in the RAFT agent was attached to the n-TiO2 surface by metalation reaction. Then, RAFT polymerization of n-vinylpyrrolidone (NVP) was subsequently conducted to graft poly(n-vinylpyrrolidone) (PNVP) onto the exterior surface of n-TiO2 nanoparticles, forming a novel core–, shell nanostructure with a mesoporous core and a polymeric nanoshell. The viscosimetry data and 1H NMR spectra were used to calculate the molecular weight of the polymer. The obtained results showed a good agreement withthe methods used. A significant enhancement in the stability of the composites was obtained as demonstrated by the TGA results. The SEM and TEM results showed that the polymer was formed on the surface of the particles. The XRD pattern of the nanoparticles of n-TiO2 presented the amorphous structure of the crystal morphology of the composites. The FTIR and UV–, visible spectroscopy results proved that the PNVP chains were grafted onto the n-TiO2 nanoparticles by surface RAFT polymerization.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 50

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
نویسندگان: 

علیجانیان زاده مهدی

اطلاعات دوره: 
  • سال: 

    1387
  • دوره: 

    3
  • شماره: 

    2
  • صفحات: 

    27-35
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    1237
  • دانلود: 

    358
چکیده: 

سه ایزوآلکیل دی تیوکربنات (زانتات) به صورت نمک های سدیم، C3H7OCS2Na (I)، C4H9OCS2Na (II) و C5H11OCS2Na (III) توسط واکنش بین CS2 با ایزوالکل مربوطه در حضور NaOH سنتز شدند و مهار آن ها بر روی فعالیت کرزولازی آنزیم تیروزیناز قارچ خوراکی Agricus bisporous خریداری شده از سیگما، امتحان شد. از (MePAPh) phenol-[azo (4-methylphenyl)]-4 به عنوان سوبسترای سنتزی آنزیم برای فعالیت کرزولازی استفاده شد. نمودارهای لاین ویور - برک نشان دادند که این لیگاندها از الگوهای رقابتی و مختلط برای مهار آنزیم استفاده می کنند. برای فعالیت کرزولازی، ترکیبات I و II از الگوی مهاری مختلط پیروی کردند، اما ترکیب III از الگوی مهاری رقابتی پیروی کرد. ثابت مهاری (Ki) ترکیبات I، II و III برای فعالیت کرزولازی به ترتیب برابر با 9.8، 7.2 و 6.1 است. این ثابت های مهاری نشان می دهند که این سه لیگاند مهارکننده های خوبی برای آنزیم تیروزیناز قارچ خوراکی اند. هم سوبسترا و هم مهارکننده می توانند به صورت تعاونی منفی بین جایگاه-های اتصال، به آنزیم متصل شوند (a>1) که میزان این تعاونی منفی با افزایش طول زنجیره آلیفاتیک در مهارکننده ها افزایش می یابد. مهار کرزولازی، به چلاته شدن یون های مس در جایگاه فعال توسط گروه S - زانتات ها بستگی دارد که همین امر باعث شده است مقادیر Ki در فعالیت کرزولازی برای هر سه لیگاند یکسان باشد.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 1237

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 358 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
اطلاعات دوره: 
  • سال: 

    1402
  • دوره: 

    44
  • شماره: 

    2
  • صفحات: 

    13-21
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    56
  • دانلود: 

    13
چکیده: 

هدف از پژوهش حاضر، سنتز، ترکیب متوکسی آمیدو زانتات MAX و نشان دارسازی آن با رادیونوکلیید mTc99 به عنوان یک عامل تشخیصی نوین جهت تصویربرداری توموگرافی رایانه ای تک فوتونی (SPECT) می­ باشد. لیگاند فوق از واکنش بین دو ماده ی کلرواستامید (Chloroacetamide) و مشتقات زانتات (Xanthate) با نسبت های مولی معین سنتز شد. سپس فرایند نشان دارسازی لیگاند MAX از طریق دوشیدن mTc99 از ژنراتور (mTc99Mo/99) و به روش مستقیم انجام گرفت. به این ترتیب که قلع کلرید به عنوان عامل کاهنده مورد استفاده قرار گرفت و اثر پارامترهایی از قبیل عوامل افزودنی از جمله اسید آسکوربیک، تغییر غلظت عامل شلات کننده و pH جهت بهینه سازی شرایط نشان دارسازی مورد ارزیابی قرار گرفت. شناسایی و تشخیص محصولات شیمیایی به وسیله ی طیف سنجی های مادون قرمز (FTIR) و رزونانس مغناطیسی هسته (NMR) انجام گرفت. میزان نشان دارسازی کمپلکس در دمای آزمایشگاه %93 برآورد شد. رادیوداروی نوین mTc-MAX99 با خلوص رادیونوکلییدی و رادیوشیمیایی بالاتر از %90 می تواند به عنوان یک عامل تشخیصی نوید بخش در مطالعات کلینیکی و پیش بالینی مورد استفاده قرار گیرد که در مطالعات آینده به آن پرداخته خواهد شد.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 56

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 13 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
اطلاعات دوره: 
  • سال: 

    2017
  • دوره: 

    36
  • شماره: 

    5
  • صفحات: 

    43-54
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    316
  • دانلود: 

    0
چکیده: 

Seven reported Xanthate ligands and their new Fe (II) complexes of formulaNa [Fe (R-OCSS)3], where R is ethyl-, propyl-, butyl-, pentyl-, Hexyl-, heptyl- and octyl-Xanthate have been synthesized.They have been characterized using elemental analysis, molar conductance, FT-IR, UV-Vis and 1H NMR spectroscopic techniques and melting-, decomposition-points for ligands and complexes respectively. All the ligands and their Fe (II) complexes have been evaluated for their antimicrobial activity against four gram-positive bacteria, four gram-negative bacteria and three fungi by agar disc diffusion technique. The MIC values of the compounds exhibited significant antifungal activity but showed lower antibacterial activity. The iron (II) complexes are found to possess higher antimicrobial activity than their counterpart ligands thus improving its antimicrobial efficacy.Hydrocarbon chain length of the ligands coordinated to Fe (II) centers seemed to be important for their antifungal as well as antibacterial activities.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 316

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 2
اطلاعات دوره: 
  • سال: 

    2024
  • دوره: 

    7
  • شماره: 

    3
  • صفحات: 

    538-554
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    17
  • دانلود: 

    0
چکیده: 

Corn stalk can be used as a potential adsorbent because of its abundance, cost-effectiveness, and accessible functional groups that allow chemical modifications. This study aims to synthesize cellulose Xanthate alginate beads (ACX beads) from corn stalks to remove methylene blue from aqueous solutions. ACX beads with various doses of porogen CaCO3 were printed using the ionic gelation method, and then characterized using FTIR, optical microscopy, and SEM-EDX. The results of the FTIR analysis reported changes in the C-S, C=S, and S-C-S vibrations that indicated the Xanthate formation. Furthermore, as the porogen dose increased, the OH intensity decreased. The high intensity of the OH group results in a high swelling process. The results of the optical microscopy analysis showed that the porogen made the ACX beads spherical. SEM-EDX analysis showed that the higher the porogen dose, the rougher the surface morphology of the ACX beads and the larger the pore diameter. The maximum adsorption capacity was obtained on ACX beads without porogen with a contact time of 360 hours. The study reveals that the kinetic adsorption followed a pseudo-second-order kinetic model proposed chemical adsorption. The larger the porogen, the more crosslinks between the divalent cations and alginate or cellulose that are formed, inhibiting the bond between the ACX beads and water and methylene blue, thereby reducing the swelling process and the adsorption capacity of the ACX beads. In addition, the pore size that is too large does not match the size of the methylene blue molecule.

شاخص‌های تعامل:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

بازدید 17

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesدانلود 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesاستناد 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resourcesمرجع 0
litScript
telegram sharing button
whatsapp sharing button
linkedin sharing button
twitter sharing button
email sharing button
email sharing button
email sharing button
sharethis sharing button