Alkaline Reagents Research Articles

Investigation of the Elemental Profile of Petroleum Jelly-Based Personal Care Products by ICP-MS

ABSTRACTHair-relaxing kits are used by many women, a high percentage of whom are African American, to transform curly hair to straight hair. Almost all varieties consist of extremely caustic solutions that demonstrate pH values in the range of 10–14. Because of the harshness of this alkaline reagent, petroleum jelly (petrolatum) is often times incorporated into the composition to protect the scalp. Petrolatum, a highly organic byproduct of crude oil, is widely used in cosmetics and topical pharmaceuticals as well. This article reports the elemental composition of various brands of hair-relaxing creams. Several sample preparation techniques were investigated for the digestion of this very organic, viscous matrix. Inductively coupled plasma-mass spectrometry was used for its multi-element capability and high sensitivity. Internal standard calibration was used in the quantitation of a select group of metals, transition metals, and metalloids (Ti, V, Cr, Co, Ni, Ga, Ge, As, Se, Rb, Sr, Zr, Nb, Mo, Ag, Cd, Cs, Ba, W, Re, Tl, Pb, U) and the established method was applied to various brands of hair-relaxing kits. Major elemental constituents were Ti, Sr, and Ba, and these were found at low µg g−1 in all brands considered.

Alkaline reagent-induced structural diversity of four metal–organic frameworks based on a flexible bicarboxylate ligand

Four new metal–organic frameworks, namely, [CdNa(bci)(H2O)3]n (1), [CdK(bci)(H2O)3]n (2), [Cd(Hbci)(H2O)]n (3) and {[(H2en)0.5Cd(bci)]·2H2O}n (4) (H3bci = bis(2-carboxyethyl)isocyanurate, en = ethylenediamine), have been prepared from H3bci and Cd(NO3)2 in aqueous solution using different alkaline reagents, namely, NaOH, KOH, triethylamine and ethylenediamine, respectively, which were characterized by single-crystal X-ray diffraction analyses, infrared spectroscopy, elemental analysis and powder X-ray diffraction. Compounds 1 and 2 are 3D heterometallic frameworks, featuring a 3-nodal 3,3,6-connected T5 type topology and a new 3-nodal 3,4,7-connected topology, respectively; complex 3 is a 3D monometallic framework with a uninodal 4-connected cag topology, while compound 4 is a 2D double-layer structure with a 2-nodal 3,6-connected kgd topology, which is extended to form a 3D supramolecular architecture by hydrogen bonds. Moreover, four new coordination modes of the H3bci ligand were observed in complexes 1–4. The results indicate that the alkaline reagents play a crucial role in the diversity of the structures and coordination modes of the H3bci ligand. The luminescence properties and thermal stabilities of these compounds were further investigated. Unexpectedly, complex 4 shows strong luminescence emission of guest ethylenediamine molecules.

The Technology Refinement of Soil Decontamination Contaminated with Petroleum Products by the Reagent Capsulation Method

The soil decontamination technology contaminated with oil products in emergency situations and due to the oil spill was examined. The decontamination technology is based on the oily waste encapsulation using alkaline reagent based on calcium or magnesium. The experimental studies results for determining the optimal reagent amount required for the efficient completion of the neutralization process of soils containing oil depending on the contamination degree and the contaminant type are presented in the article.

Formation of Resins in Used Oils as a Result of Conformation-Structure Change of Their Hydrocarbons

The mechanism of formation of resinous compounds during use of industrial and motor oils was studied by IR and NMR spectroscopy. Based on a comparative analysis of the spectra of samples of the used oil and the resins separated from it and the spectrum of fresh oil it was concluded that, besides oxidative mechanism, resinous compounds are formed in the oils as a result of oligomerization of the hydrocarbons. The molecules of the latter suffer, in the thermomechanical deformation process, profound stereostructural change at the level of distortion of the torsion angles and bond lengths. This leads to increase of the potential energy, corresponding dissociation of the R–C⋯H bonds in the hydrocarbons, and increase of their acidity, which stimulates oligomerization at these protonated bonds, i.e., initiates the oligomerization process and formation of aromatic hydrocarbons, or aging of the oil. The distortion of the stereostructure of the hydrocarbons in the oil during use remains in the mechanochemical memory of the molecules. This is why the purified used oil, even without oxidation of the hydrocarbons, becomes dark during storage because of the chromophoric –C–H acids that are formed. The latter are neutralized in the presence of alkaline reagents.

Alternative Alkaline Conditioning of Amidoxime Based Adsorbent for Uranium Extraction from Seawater

Alkaline conditioning of the amidoxime based adsorbents is a significant step in the preparation of the adsorbent for uranium uptake from seawater. The effects of various alkaline conditioning parameters such as the type of alkaline reagent, reaction temperature, and reaction time were investigated with respect to uranium adsorption capacity from simulated seawater (spiked with 8 ppm uranium) and natural seawater (from Sequim Bay, WA). An adsorbent (AF1) was prepared at the Oak Ridge National Laboratory by radiation-induced graft polymerization (RIGP) with acrylonitrile and itaconic acid onto high-surface-area polyethylene fibers. For the AF1 adsorbent, sodium hydroxide emerged as a better reagent for alkaline conditioning over potassium hydroxide, which has typically been used in previous studies, because of higher uranium uptake capacity and lower cost over the other candidate alkaline reagents investigated in this study. Use of sodium hydroxide in place of potassium hydroxide is shown to result in a 21...

Controllable synthesis of layered Co–Ni hydroxide hierarchical structures for high-performance hybrid supercapacitors

A facile solvothermal method is developed for synthesizing layered Co–Ni hydroxide hierarchical structures by using hexamethylenetetramine (HMT) as alkaline reagent. The electrochemical measurements reveal that the specific capacitances of layered bimetallic (Co–Ni) hydroxides are generally superior to those of layered monometallic (Co, Ni) hydroxides. The as-prepared Co0.5Ni0.5 hydroxide hierarchical structures possesses the highest specific capacitance of 1767Fg−1 at a galvanic current density of 1Ag−1 and an outstanding specific capacitance retention of 87% after 1000 cycles. In comparison with the dispersed nanosheets of Co–Ni hydroxide, layered hydroxide hierarchical structures show much superior electrochemical performance. This study provides a promising method to construct hierarchical structures with controllable transition-metal compositions for enhancing the electrochemical performance in hybrid supercapacitors.

Speciation Analysis of (129)I and (127)I in Aerosols Using Sequential Extraction and Mass Spectrometry Detection.

A new analytical method has been developed for speciation analysis of (127)I and (129)I in aerosols collected on polypropylene (PP) filter paper. Iodide, iodate, NaOH soluble iodine, and insoluble iodine were separated from aerosols using sequential extraction, chromatography separation, and alkaline ashing and measured using inductive coupled plasma mass spectrometry (ICP-MS) for (127)I and accelerator mass spectrometry (AMS) for (129)I. Parameters affecting the leaching efficiency and stability of iodine species, such as leaching time and temperature, amount of alkaline reagent for ashing, ashing temperature and time, and iodine protective agent, were investigated and optimized. It was observed that long time water leaching would change inorganic iodine species due to photochemical oxidation of iodide on the PP filter surface. NaOH leaching can only extract less than 60% of iodine from the studied aerosol filters even under heating, implying that total (129)I in aerosol might be underestimated by NaOH leaching. The addition of a reductive agent significantly reduced the loss of iodine during alkaline ashing from more than 35% to 4%, efficiently improving the separation efficiency of iodine in aerosols. Speciation analysis of (129)I and (127)I in aerosol samples collected at Risø, Denmark using the developed method shows that the measured values of total (129)I and (127)I are in good agreement with the sum of all iodine species for each isotope, confirming the reliability of the proposed method. Similar distribution patterns between (129)I and (127)I species show that iodine is enriched in NaOH leachable and insoluble species and depleted in water-soluble species, as observed in all aerosol samples.

Validation of Soil Phosphate Removal by Alkaline and Acidic Reagents in a Vertosol Soil using XANES Spectroscopy

There is a paucity of information on the soil phosphorus (P) forms removed by alkaline and acidic reagents in Vertosols. The first aim of this study was to identify which soil phosphates are removed by a two-step sequential fractionation (0.1 M NaOH and 1 M HCl) and by a dilute acid extractant (0.005 M H2SO4; Bureau of Sugar Experiment Stations (BSES) soil P test) on an “untreated” Vertosol using P K-edge x-ray absorption near-edge structure (XANES) at the Australian Synchrotron. There was supporting evidence that the 0.1 M sodium hydroxide (NaOH), 1 M hydrochloric acid (HCl), and 0.005M sulfuric acid (H2SO4) extractants remove soil phosphates according to the chemical solubility of known P minerals. The XANES spectra revealed the 1 M HCl and 0.005 M H2SO4 extractants remove calcium (Ca) phosphates from Vertosols, suggesting the latter extractant could be used as an alternative for a rapid and cost-effective measure of Ca phosphates in Vertosols.

Removal of dissolved humic acid from water by coagulation method using polyaluminum chloride (PAC) with calcium carbonate as neutralizer and coagulant aid

Coagulation experiments were performed to find out the optimum coagulant and alkaline chemical for the removal of humic acid (HA) from environmental water. This research clearly indicates the effectiveness of coagulation method using polyaluminum chloride (PAC) with calcium carbonate as neutralizer and coagulant aid to remove HA. The removal of HA was evaluated from absorbance at 260nm and concentration of dissolved organic carbon (DOC). The highest removal ratio was found to be 96.6% for the absorbance of HA and 91.6% for DOC concentration when 30mg/L of PAC with calcium carbonate (CaCO3) was used as an alkaline reagent. In this method, the sludge volume (SV) was reduced about half compared with the PAC method using NaOH as neutralizer. Ca2+ which is derived from CaCO3 makes HA colloid size bigger and easier to form flocks because of the compression in the electrical double layer (EDL) between HA colloids. The adsorption of HA onto porous CaCO3 particles also plays an important role. The experiments conducted with sample water collected from Sebangau River, Indonesia consists of 33.4mg/L of DOC and was found to have a removal efficiency of 86.5%, whereby the final concentration of DOC was 4.5mg/L. These results suggested that CaCO3 requires a lesser amount of coagulants and also shortens the settling time. This proposed technique provides a more effective and conventional removal method for HA by coagulation–precipitation processes.

Size-controlled synthesis of SnO2 quantum dots and their gas-sensing performance

Tin dioxide quantum dots (TQDs) with controllable size were synthesized by changing the amount of alkaline reagent in the hydrothermal process. The gas-sensing properties were investigated by operating chemoresistor type sensor. The morphology and structure were characterized by X-ray diffraction, scanning/transmission electron microscopy, UV–vis and Raman spectrometry. The as-synthesized SnO2 shows the characteristics of quantum dots and the narrowest size distribution is about 2–3nm. The gas-sensing results indicate that the responses are strongly dependent on the size of quantum dots. TQDs with different sizes exhibit different sensitivities and selectivities to volatile toxic chemicals such as aldehyde, acetone, methanol, ethanol and amine. Especially, when the sensors are exposed to 100ppm triethylamine (TEA), the sensing response value of TQDs with small size is two times higher than that of the large-size TQDs. The maximum response values of TQDs to 1ppm and 100ppm TEA are 15 and 153, respectively. The response time is 1s and the recovery time is 47s upon exposure to 1ppm TEA. The results suggest that it is an effective method by regulating the size of SnO2 quantum dots to detect low-concentration hazardous volatile compounds.

Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS

The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles.

Enhancement of the electrokinetic remediation method of fine-dispersed clay soils

The possibility of application of the modified electrokinetic treatment method to removal both inorganic and organic contaminants from clay soils has been demonstrated. The proposed improvements include the adjustment of pH of the soil pore solution, as this parameter is one of the major factors determining the treatment efficacy. The modification consists in replacement of the conventional acidic or alkaline reagents with neutral ones, thus enhancing the ecological compatibility of the detoxification process.

An improved analytical method for iodine-129 determination in low-level radioactive waste

Abstract In this study, an alkaline-digestion pretreatment and a subsequent ICP-MS measurement were conducted for iodine-129 (I-129) determination in low-level radioactive waste. A TMAH + H2O2 + Triton X-100 mixed alkaline digestion was the most effective mixture for I-129 determination. Using this alkaline reagent, a high level of I-129 recovery (101 ± 6%) was achieved for the analysis of the I-129-spiked standard reference materials NIST 2709 and 2711. Importantly, the I-129 concentrations determined for ten real samples provided by the Lan-Yu radioactive waste temporary storage site were found to be below the detection limit (0.011 mg/kg). This value was only approximately 30–70% of the values determined using the I-129/Cs-137 scaling factor. This means that using the I-129/Cs-137 scaling factor severely overestimates the I-129 concentration in these low-level radioactive wastes. We therefore suggest that a detailed re-inspection of the I-129/Cs-137 scaling factor should be performed to appropriately categorize these low-level radioactive wastes.

Morphologies-controlling synthesis of silicalite-1 and its adsorption property

The morphologies-controlled silicalite-1 with mesoporous structure was synthesized in fluoride media and the adsorption properties were also investigated. The results show that the morphology of samples can be tailored by synergy effect of fluoride ion, alkaline reagent and reaction condition. The brick and sword-like silicalite-1 is more effective to adsorb CO2 and CH4 compared with microsphere, which suggests that the morphology-controlled silicalite-1 with mesoporous structure has a potential application in decreasing harmful gas emission of cigarette smoking.

Optimisation of alkaline reagent based chemical pre-treatment of Brewers spent grains for bioethanol production

The pre-treatment step of lignocellulosic ethanol production is recognised as the most energy intensive part of the overall process. Key objectives are thus that pre-treatments should operate effectively at low to moderate temperatures and at high percentage solids, in order to minimise energy inputs.Chemical pre-treatment of BSG using alkaline reagents, at moderate process temperatures, was optimised in terms of sugar release following enzymatic saccharification of the pre-treated residues. An excess of Celluclast® cellulase enzyme was used to compare various pre-treatments in terms of the % of theoretical sugars that could be liberated. Using alkaline peroxide (5% H2O2/NaOH at pH 11) up to 87% of the theoretical glucose yield (based on composition of the pre-treated residue) was attained following pre-treatment of BSG at 25% (w/v) solids loading for 5h at 100°C. Pre-treatment using 5% NaOH at 25% (w/v) solids loading for 12h at 50°C liberated 92% of theoretical glucose This pre-treatment remained effective with process times as short as 2h (ca. 70% of theoretical glucose). For NaOH pre-treatments the extent of lignin removal from pre-treated residues broadly correlated with the efficacy of the pre-treatment in terms of final saccharification yields. However, for alkaline peroxide pre-treatments no such correlation was observed.Saccharified BSG was prepared following treatment with the optimised NaOH or alkaline peroxide pre-treatments and the resultant hydrolysates fermented with Saccharomyces cerevisiae. Fermentation performance was superior for the NaOH pre-treated samples relative to alkaline peroxide generated feedstocks with shorter lag phases and faster attenuation rates. Mean ethanol concentrations of ca. 17.3g/L and 8.4g/L were achieved for the NaOH and alkaline peroxide fermentations respectively which corresponded to 81% and 43% of theoretical ethanol yields.

The Novel Study on the Reaction Mechanism and Structural Changes of Co(OH)2 By Using Synchrotron X-Ray Techniques

Graphitic carbon is extensively used as anode material in most of the commercial lithium-ion batteries (LIBs) due to its low cost and high coulombic efficiency. However, capacity of carbon anode (372mAh/g and 830mAh/mL) is limited by the reversible electrochemical intercalation of lithium ions in its structure. So, alternative research directions and different anode materials are currently being investigated with an aim to achieve high capacity and cycling stability. Recently nano-material research has shed light on many high performing materials. Among these, cobalt hydroxide has been recognized as one of the potential candidates for anode materials because of its novel electric and electrochemical properties[1]. Co(OH)2 with a sheet-like structure tends to form a layered assembly, thus it has the benefit of improved ion transport and better contact of electro-active materials with electrolyte. Several methods have been used to synthesize the hexagonal β-Co(OH)2 nano sheets including facile hydrothermal and homogeneous precipitation with sodium hydroxide as the alkaline reagent. Co(OH)2-Graphene Nano Sheet (GNS) composite was reported in 2010[2] as anode material for LIBs with superior electrochemical performance and its reaction mechanism was suggested as: Co(OH)2 + 2Li+ +2e- → Co + 2LiOH (577mAh/g). GNS acted as synergistic effect to synthesized material for achieving higher capacity (1120mAh/g) because GNS could relieve the volume expansion during cycling and also, give excellent electronic conductivity. Co(OH)2-nanosheets/ Co3O4-nanoparticle hierarchical structure has also been reported[3] as anode material for LIB’s with enhanced capacity and performance. However, despite diverse studies on Co(OH)2 material, pure Co(OH)2 nanosheets still have poor cycling performance, which may be due to insufficient electrolyte soaking between layers and large volume changes during the cycling process. Besides, pure Co(OH)2 nanosheets show higher reversibly capacity beyond the reported mechanism. In order to improve the Co(OH)2 electrode performance, primary research should first be focused on the study of pure Co(OH)2 to better understand its reaction mechanism.Herein, we successfully synthesized colloidal silica assisted sheet-like nano-structured Co(OH)2 using cobalt (Ⅱ) nitrate hexahydrate (Co(NO3)2∙6H2O, 97%, m.p. 55C, Aldrich) as precursor through simple synthetic strategy. This research also included its novel reaction mechanism during electrochemical cycling with lithium. Structural and electrochemical properties of synthesized material were studied by electrochemical tests and combination of the synchrotron radiation based X-ray diffraction (XRD)/ X-ray absorption spectroscopy (XAS) techniques. Changes in the bulk structure were studied by XRD whereas local structure changes around Co during cycling were systematically investigated by recorded XAS data. Based on these results, we propose novel reaction mechanism of the nano-structured Co(OH)2 material during electrochemical cycling. More detailed discussion will be presented at the time of meeting.[1]. Huang, X.-l et al., Journal of Materials Chemistry, 2012. 22(9): p. 3764.[2]. He, Y.-S et al., Electronbbn chemistry Communications, 2010. 12(4): p. 570-573. [3]. Dong, Q et al., Materials Research Bulletin, 2011. 46(8): p. 1156-1162.

Investigation on multiple benefits of wet ESP for emission control in an Indian coal fired thermal power plant

In this article, the operation of wet electrostatic precipitators (WESP) as air pollution control device in an Indian coal fired thermal power plant has been investigated in respect of its efficacy in removing particulate laden gaseous emissions. The WESP was installed for reducing the particulate matter (PM) emission to meet the Indian stack emission standard of PM. Interestingly, the study reveals that the WESP reduced the SO2 and CO2 emissions potentially. The system, therefore, functions also simultaneously as a CO2 capture system. Since CO2 is a green house gas (GHG), operating a WESP for cleaning flue gas of a coal fired thermal power plant can be considered as a GHG emission mitigation option as well. The level of NOx emission could not be conclusively analyzed perhaps might be due to air dilution of the flue gas. It is finally suggested that the plant operators would like to operate the plant using dilute alkaline reagent replacing the water as the scrubbing medium so as to obtain multiple benefits of cleaning all acidic gases by the WESP followed by better ash management.

Mechanochemical Neutralization of Hypericin in Hypericum perforatum Studied by Spectroluminescence

The speciation of hypericin in plant raw material was determined. The solid-state mechanochemical reaction of hypericin in plant raw material with alkaline reagents was studied in order to produce a very soluble salt species.

Comparison of seven chemical pretreatments of corn straw for improving methane yield by anaerobic digestion.

Agriculture straw is considered a renewable resource that has the potential to contribute greatly to bioenergy supplies. Chemical pretreatment prior to anaerobic digestion can increase the anaerobic digestibility of agriculture straw. The present study investigated the effects of seven chemical pretreatments on the composition and methane yield of corn straw to assess their effectiveness of digestibility. Four acid reagents (H2SO4, HCl, H2O2, and CH3COOH) at concentrations of 1%, 2%, 3%, and 4% (w/w) and three alkaline reagents (NaOH, Ca(OH)2, and NH3·H2O) at concentrations of 4%, 6%, 8%, and 10% (w/w) were used for the pretreatments. All pretreatments were effective in the biodegradation of the lignocellulosic straw structure. The straw, pretreated with 3% H2O2 and 8% Ca(OH)2, acquired the highest methane yield of 216.7 and 206.6 mL CH4 g VS −1 in the acid and alkaline pretreatments, which are 115.4% and 105.3% greater than the untreated straw. H2O2 and Ca(OH)2 can be considered as the most favorable pretreatment methods for improving the methane yield of straw because of their effectiveness and low cost.

Evaluation of alkaline pre-treatment of PLLA fibers for biomimetic hydroxyapatite coating

A poly(l-lactic acid) (PLLA) and hydroxyapatite (HA) composite was formed via a biomimetic coating process. Before treatment in a modified-simulated body fluid (m-SBF), the surfaces of the PLLA fibers were etched with alkaline reagents to make the polymer surface easier for apatite to nucleate and grow. Several elements of this etching procedure (including the etching reagent, concentration, and length of pre-treatment) were varied to determine the optimal combination for producing a predictable HA coating with the desired properties of consistent coating distribution and thickness. The alkaline etching reagents used in this study were sodium hydroxide (NaOH), sodium hypochlorite (NaOCl), calcium hydroxide (Ca(OH)2), and calcium hypochlorite (Ca(OCl)2). The weight gained through m-SBF coating, changes in the mechanical properties of the PLLA, and HA coating morphology were observed to determine the effects of different pre-treatment strategies on the biomimetic coating process. It was confirmed that the most effective etching reagents are Ca(OH)2 and Ca(OCl)2. It was also found that decreased etching reagent concentration leads to a decrease in HA coating and increased etching time increases HA deposition.