Nanocomposite fibers produced via electrospinning have very large surface area by virtue of their nanometer diameter sizes thereby making them very attractive for various applications such as for adsorption of contaminants from wastewater. In this study, a highly adsorbing nanoparticle, iron-modified montmorillonite was used as filler in the nanocomposite. The effects of polymer solution and suspension properties such as polymer concentration, clay loading, and filler type on the electrospinning of the nanocomposite were investigated using a 2k factorial design of experiment. The types of montmorillonite used were zero valent iron-MMT (ZVIMMT) and iron (III)-MMT (FeMMT). It was found from the SEM images that finer fibers were generated from suspensions with lower polymer concentration in the solution specifically at 5 wt% and from suspensions with ZVIMMT particles as filler. However, a common defect in nanofibers called beads was also observed in the fibers produced from 5 wt% polymer concentration. TEM micrographs confirmed that the ZVIMMT fibers have smaller diameter than the FeMMT fibers. In addition, it was recognized that the layered structure of the clay is still intact after the electrospinning process. The XRD pattern of the fibers revealed that the clay particles were intercalated with the polymer molecules based on the calculated d-spacing. Furthermore, elemental analysis on the bead and string regions of the electrospun fibers confirmed the presence of polymer and montmorillonite particles in both regions.
The release of arsenic to aqueous environment imposes threats to human health. Montmorillonite supported zero-valent iron (ZVI-MMT) is a material with capability of immobilizing arsenic from aqueous environment. The arsenic adsorption efficiency of ZVI-MMT was obtained. In addition, adsorption kinetics of arsenic contaminated water on the material was determined. Arsenic and iron content was quantified by an inductively coupled plasma mass spectrometer (ICP-MS), interplanar distance of the adsorbent was measured by x-ray diffractometer (XRD), and the morphology of the adsorbent was obtained from a transmission electron microscope (TEM). Isotherm data were analyzed using the Langmuir and Freundlich isotherms. The data fitted well to Langmuir isotherm with derived adsorption capacity of 20.1 mg/g. Kinetics data were analyzed using intra-particle model, Elovich equation, pseudo first-, and pseudo second-order models. Elovich equation and pseudo second-order equation fitted the experimental data with pseudo second-order rate constant of 61.2 x 10-4 g/mg-min.
10Copper deposition from solutions using high concentration of acid, metal ions and 11 polyethylene glycol (PEG), and bis-(3-sulfopropyl) disulfide (SPS) and chloride ions (Cl -) is 12 well known. A recent maskless micropatterning technology, which has the potential to 13 replace traditional photolithographic process, called EnFACE, proposed using an acid-free, 14 low metal ion solution which is in direct contrast to those used in standard plating 15 technology. In this work copper has been deposited using standard electroplating solutions 16 and those used in the EnFACE process. In the standard electrolyte 0.63 M CuSO4 and 2.04 M 17 H2SO4 has been used, along with Gleam additives supplied by Dow Chemicals. For the Enface 18 electrolyte, copper deposition has been carried out using without any acid, and with Morphological analysis (SEM and EBSD) was done using the JEOL JSM-5300LV. 70Resistivity of the plated films were measured using the Signatone Pro4 (four point probe) 71 system in the Electronics and Electrical Engineering department Newcastle University UK. Prior to actual plating, the stainless steel coupons were cleaned with concentrated 93 HNO3, and then rinsed with water for 1 minute. The coupons were mechanically polished 94 using silicon carbide sheets, starting at grit #220 and progressing to grit #4000. One side of 95 the coupon was coated with the photoresist, and left to dry. The exposed side of the coupon 96 was swabbed with ethanol for 30 seconds and again allowed to dry. Chemicals and Electrolytes 97Electrodeposition was carried out in direct current (DC) mode. The counter and 98 working electrode was set-up in the plating cell containing different electrolytes. Table 2 99 shows the plating parameters used for the different experiments. These parameters were 100 derived from polarization experiments that yielded limiting current regarding each bath 101 type. Since the deposits become rougher as they approach the limiting current [21], the 102 current was set at a fraction of this value to ensure that dendritic copper was not plated. 103The total plating time was calculated to obtain a copper film with thickness of 25 um. 104After the allotted deposition time was reached, the coupons were removed from the 105 solution and washed with deionized water for 1 minute. The surface was dried using a lint 106 free cloth and left to dry in air. The plated copper films were then carefully peeled off from 107 the stainless steel substrate, and were prepared for subsequent characterization. Each 108 experiment was repeated three times to check for reproducibility. 109For SEM and EBSD analysis, a 2x2 cm 2 area was cut out from the central portion of 110 the copper coupon. For mechanical and resistivity testing, the whole coupon was used. The rightmost column in Table 2 gives a summary of the calculated grain size of using EnFACE electrolyte. Clearly, the progressive addition of additives created a more 171 resistive copper deposit. Furthermore, the resistivity of some of the EnFA...
While nickel (Ni) electroplating has been successfully performed using ionic liquids in the past, few studies have reported on the trench-filling characteristics of this process useful for electroforming Ni. This study aimed to deposit and characterize the electrodeposited nickel using an ethaline-based nickel-plating bath with and without ethylenediamine (en). The conductivity of the plating bath was improved, while viscosity was slightly reduced upon the addition of en. Cyclic and linear sweep voltammetry revealed that en acted as a suppressor, significantly reducing the bath’s plating rate. The Hull cell was used to determine the optimum operating current density for each bath. The additive-bearing bath produced more compact deposits, better deposit grain morphology, and improved trench-filling (> 95% filling) characteristics compared to its additive-free counterpart. The enhanced super-filling characteristics may be explained by the differential acceleration curvature-enhanced accumulation acceleration (CEAC) model. SEM analysis showed that the deposits possessed a particulate or nodular structure, whereas EDS confirmed the presence of Ni in the deposit. The Ni deposited using the bath without additives had larger particulate grains than those using the additive-bearing bath. Higher Ni amounts were obtained in the additive-laden bath. The use of additives is a promising approach for improving the super-filling characteristics of ionic liquid plating baths.
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