A low-cost green approach for synthesis of lead oxide from waste lead ash for use in new lead-acid batteries

This paper proposes a novel method relating to the recycling of waste lead ash originated from procedure of lead alloy production. The spent lead ash was first disposed by acetic acid leaching system, where lead ash structure wrapping impurities would be destroyed. The synthesis of lead oxide products was conducted at a lower temperature of 90 °C. The effect of molar ratio of CH₃COOH to lead content of the ash on leaching efficiency was studied through the acetic acid leaching system. The results demonstrate that 84.6% of lead could be obtained in the leaching solution, while merely 0.7% of Fe blend in solution within a leaching time of 120 min. In the stage of lead oxide synthesis from leaching solution, the yield of lead oxide products could reach up to 94.4% when the molar ratio of NaOH to lead in filtrate was 2.5. This novel green method could shed light on the reuse of lead from exhausted ash with a much more convenient and environmentally friendly procedure.     

Effect of demineralization of El-lajjun Jordanian oil shale on oil yield

The effect of demineralization on oil yield and mineral composition of Jordanian oil shale was investigated. A standard digestion procedure using a range of inorganic and organic acids including HCl, HNO₃, HF, and CH₃COOH was used to enhance the oil recovery of oil shale samples collected from the El-lajjun area. The total yield of the digested samples, as determined by Fischer Assay, has shown a maximum value (two folds the untreated sample) obtained when using CH₃COOH. The kaolin in the treated oil shale with a high concentration of CH₃COOH is believed to have transformed to illite as found in the XRD analysis. The treatment of oil shale using HCl has shown an increased ratio of oil to gas as a result of the digestion of calcite in the oil shale. At higher concentrations of HNO₃, the acid is believed to react with the kerogen in the oil shale resulting in high levels of low molecular weight compounds. Therefore, the amount of non-condensable gases produced by Fischer assay after treatment with a high concentration of HNO₃ is relatively high. HF is believed to drive off water from the oil shale by dissolving the clay minerals leading to increased oil to gas ratio.     

Nitric acid purification from admixtures of volatile acids by fractionation during waste evaporation at a spent nuclear fuel reprocessing company

We present the results of the computer simulation of a method for better purification of nitric acid from HF and CH₃COOH admixtures by creating a stripping section in the fractionation column with HNO₃ scrubbing and by the feeding of a parasitic water flow to the bottom section. The production column in the evaporator section of the RT-1 plant at the PA ??Mayak?? was upgraded using the calculation results and test trials on real process high-level waste were performed, which made it possible to improve the purification of regenerated 12 mol/L HNO₃ from HF and simultaneously from HCl by a factor of 3?C5. The specification figures for three flowsheet of nitric acid regeneration that were used at different times since 1979 for commercial purification from halogens and radioactive contaminants were compared.     

New catalyst system for easy-care cotton finishing

A new catalyst system, based on a mixture of boron trifluoride–acetic acid complex (BF₃·2CH₃COOH) and magnesium chloride hexahydrate (MgCl₂·6H₂O), has been examined in cotton finishing treatment for producing easy-care properties. It provides strong catalysis in crosslinking cotton with a series of N-methylol finishing agents when the pad-dry-cure process is applied. Curing can be carried out at a temperature of 130–150°C for a period of 1–3 min, dependent on the temperature used. The resilience and abrasion resistance properties as well as the degree of polymerization (D.P.) of the crosslinked cotton so obtained were equivalent or slightly better than those of crosslinked cottons catalyzed by conventional catalysts. The influence of the new catalyst as well as a number of conventional catalysts, viz., ammonium chloride, ammonium dihydrogen phosphate, magnesium chloride hexahydrate, and zinc nitrate hexahydrate, on some properties of cotton fabrics was also investigated. The behavior of these catalysts in the presence of the N-methylol finishing agent was quite different from their behavior in its absence. With the exception of ammonium salts, the D.P. of crosslinked cotton was much higher than that of cotton treated with the catalyst only. The opposite holds true for the abrasion resistance.     

Preparation of carboxylic acids from hydroxy compounds by oxidation with ozone

Various mono- and dicarboxylic acids were obtained with appreciable yields from saturated hydroxy compounds by oxidation in aqueous acetic acid with a mixture of ozone and oxygen followed with oxygen. The starting materials and the mono- and dicarboxylic acids obtained were as follows: Primary alcohols RCH₂OH → RCOOH; α,ω-glycols HOCH₂(CH₂)_nCH₂OH → HOOC(CH₂)_nCOOH; secondary alcohols and 12-hydroxyoctadecanoic acid R₁CH₂CH(OH)CH₂R₂ → R₁COOH + R₂CH₂COOH + R₁CH₂COOH + R₂COOH; alicyclic alcohols CH₂(CH₂)_nCHOH → HOOC(CH₂)_nCOOH; 9,10-dihydroxyoctadecanoic acid CH₃(CH₂)₇CH(OH)CH(OH) (CH₂)₇COOH → CH₃(CH₂)₇COOH + HOOC(CH₂)₇COOH. Small amounts of aldehydes, ketones, and carboxylic acids having fewer carbon atoms than those of the carboxylic acids formed as main products were also detected from some of the oxidation products.     

Changes to the organic functional groups of an inertinite rich medium rank bituminous coal during acid treatment processes

A South African inertinite rich medium rank bituminous coal was subjected to a series of acid treatment steps using concentrations of HF and HNO₃ ranging between 1.5 and 4 M, temperatures between 65 and 80 °C and reaction time between 1.5 and 3 h for each acid. A HF and HCl procedure was used to reduce mineral matter to less than 2.5%. Analyses indicate that oxygen and nitrogen containing species are incorporated in the coal structure during the HF/HNO₃ leaching processes, but not during the HCl/HF/HCl procedure. The HF/HNO₃ methods lead to increased amounts of = N-OH groups formed on the remaining coal structure, whereas the HCl/HF/HCl procedure did not. The -COOH content upon HCl/HF/HCl treatment increased slightly possibly due to protonation of COO⁻ groups by HCl. The results show that the CO₂ reactivity doubled after the HF/HNO₃ procedures and increased by a factor of 2.5 for the HCl/HF/HCl treatment. Surface areas of the treated coal samples increased with the highest increase for the HCl/HF/HCl method. The increased surface areas may cause the increased CO₂ reactivity. The results indicate that the described acid treatment procedures with mixtures containing nitric acid have slight, but measurable, effects on the coal structure.     

Dispersion behaviour of laser-synthesized silicon carbide nanopowders in ethanol for electrophoretic infiltration

SiC nanopowders of 30 nm in diameter were successfully synthesized by laser-pyrolysis with high production rate (1.7 kg/h) and high quantity (>2 kg). The as-synthesized nanopowders were heat-treated in order to slightly oxidize the surface. It was shown that the heat-treatment does not modify structural properties or morphology but modifies the surface chemistry. Ethanolic suspensions with polyethylenimine (PEI) as dispersant were prepared from the heat-treated powders. The suspensions properties were characterized in terms of rheology, zeta potential and size distribution before and after operational pH adjustment with hydrochloric acid (HCl 1 M) or acetic acid (CH₃COOH). High concentrated suspensions (28 wt%) with low viscosity were obtained after pH adjustment with CH₃COOH. Electrophoretic infiltrations of carbon preforms carried out with these suspensions lead to a high quality infiltration of the inter-tows area as well as of the intra-tows area, some tows being completely filled with the nanopowders.     

Effects of Different Treatments on the Inactivation of Various Seedborne Viruses in Some Vegetables

In this study, we considered the efficacy of seed treatments for the inactivation of some seedborne viruses in tomato, pepper, melon, squash, bean and lettuce seeds, which are essential for human nutrition and seed production in our country. A total of 325 seed samples obtained from various farmers and foundations were tested by DAS-ELISA and RT-PCR procedures. Eight seed lots infected with Tomato mosaic tobamovirus (ToMV), Tobacco mosaic tobamovirus (TMV), Cucumber mosaic cucumovirus (CMV), Soybean mosaic potyvirus (SMV) and Lettuce mosaic potyvirus (LMV) were selected as research materials. Virus inactivation treatments were made by using acetic acid (CH₃COOH), hydrogen peroxide (H₂O₂), hydrochloric acid (HCl), sodium hypochlorite (NaClO), Triton X 100, dry heat, heated water, ozone (O₃), and UV (305 nm wavelength). The most effective treatments for reducing virus concentration were HCl, heated water (65 °C) and ozone (10 g m^?3). These treatments reduced concentrations of seed-borne viruses in ranges of 51%, 42%, and 32%, respectively. Other treatments were less effective and reduced virus concentrations in the range of 27%–12%. HCl and ozone treatments were the most effective and applicable methods because they did not have negative effect on seed germination.     

Chemical synthesis and characterization of some conducting polyaniline derivatives: Investigation of the effect of protonation medium

Poly(o‐toluidine) (POT) and poly(2‐chloroaniline) (P2ClAn) emeraldine salts were synthesized chemically by using formic (HCOOH), acetic (CH₃COOH), propionic (C₂H₅COOH), and boric (H₃BO₃) acids. Ultraviolet‐visible absorption spectra (UV–Vis) analysis results indicated that POT has the better protonation effects than P2ClAn. Among the POTs synthesized using the four different acids, POT(H₃BO₃) showed the least protonation effect. The conductivities of prepared polymers were measured by a four‐probe technique. The highest conductivities were obtained in POTs synthesized by using formic, acetic, and propionic acids. Magnetic susceptibility measurements of the polymer salts were analyzed by using Gouy scale and it was found that POT(CH₃COOH) and POT(C₂H₅COOH) salts are of bipolaron structure; other polymer salts are of polaron structure. The characterization of the polymers were investigated by Fourier infrared spectroscopy (FTIR), UV–Vis, thermogravimetric analysis, and scanning electron microscopy. It was observed from UV–Vis spectra of the emeraldine salt of POT that wavelengths belonging to π → π* transitions shifted to shorter wavelengths with increasing pKa values of acids. POT and P2ClAn synthesized in four different protonation media decomposed with three‐step and three‐ or two‐step weight loss, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1993–2000, 2002; DOI 10.1002/app.10487     

Dodecylhydroxydiphosphonic Acid for Solvent Extraction

Abstract

The extraction behavior of Zn(II) and Cu(II) in acetate media has been investigated using dodecylhydroxydiphosphonic acid, DHDPA, which was previously synthesized and characterized. The extraction of both cations was carried out in different media with the addition of CH₃COOH, HCl or H₂SO₄ at different pH. The maximum extraction yield of 80% for zinc, was obtained in one step after the addition of sulfuric acid at pH_i=5.5 and for copper after the addition of 10 mg of sodium acetate. The authors plan additional tests using polar solvents.     

Novel sulfur—containing benzophenone derivative as radical photoinitiator for photopolymerization

A novel, highly efficient, polymerizable sulfur‐containing photoinitiator for free radical polymerization, benzophenone thio‐acetic acid (BP‐S‐CH₂‐COOH) was synthesized, characterized, and compared to photoinitiator parameters of the benzophenone (BP) and benzophenone/(phenylthio)acetic acid couple. The photoinitiator possesses a greatly redshifted UV maximal absorption in comparison to BP. Laser flash photolysis studies suggest that photoinitiator radicals are generated by photocleavage of C? S bond. Photopolymerization of 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol triacrylate (TMPTA) demonstrated that one‐component system BP? S? CH₂? COOH is more efficient for polymerization than two‐component system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Single‐Pot Ethane Carboxylation Catalyzed by New Oxorhenium(V) Complexes with N,O Ligands

The oxorhenium(V) chelates [ReOCl(N,O‐L)(PPh₃)] [N,O‐L=(OCH₂CH₂)N(CH₂CH₂OH)(CH₂COO) ( 2 ), (OCH₂CH₂)N(CH₂COO)(CH₂COOCH₃) ( 3 )] and [ReOCl₂(N,O‐L)(PPh₃)] [N,O‐L=C₅H₄N(COO‐2) ( 4 ) C₅H₃N(COOCH₃‐2)(COO‐6) ( 5 )] have been prepared by reaction of [ReOCl₃(PPh₃)₂] ( 1 ), in refluxing methanol, with N,N‐bis(2‐hydroxyethyl)glycine [bicine; N(CH₂CH₂OH)₂(CH₂COOH)], N‐(2‐hydroxyethyl)iminodiacetic acid [N(CH₂CH₂OH)(CH₂COOH)₂], picolinic acid [NC₅H₄(COOH‐2)] or 2,6‐pyridinedicarboxylic acid [NC₅H₃(COOH‐2,6)₂], respectively, with ligand esterification in the cases of 3 and 5 . All these complexes have been characterized by IR and multinuclear NMR spectroscopy, FAB⁺‐MS, elemental and X‐ray diffraction structural analyses. They act as catalysts, in a single‐pot process, for the carboxylation of ethane by CO, in the presence of potassium peroxodisulfate K₂S₂O₈, in trifluoroacetic acid (TFA), to give propionic and acetic acids, in a remarkable yield (up to ca. 30%) and under relatively mild conditions, with some advantages over the industrial processes. The picolinate complex 4 provides the most active catalyst and the carboxylation also occurs, although much less efficiently, by the TFA solvent in the absence of CO. The selectivity can be controlled by the ethane and CO pressures, propionic acid being the dominant product for pressures about ca. 7 and 4 atm, respectively (catalyst 4 ), whereas lower pressures lead mainly to acetic acid in lower yields. These reactions constitute an unprecedented use of Re complexes as catalysts in alkane functionalization.     

Gas/Aerosol Distribution of Formic and Acetic Acids

Data and correlations for evaluating the gas/aerosol equilibrium of formic and acetic acids are developed. The species considered include HCOOH(g), CH₃COOH(g), HCOOH(aq), CH₃COOH(aq), HCOO^?, CH₃COO^?, HCOONa(s), CH₃COONa(s), HCOOK(s), (HCOO)₂Ca(s), and (CH₃COO)₂Ca(s). Based on available thermodynamic data, we show that the gas /aerosol distribution of formic and acetic acids is strongly on the gas-phase side for typical sulfate/ nitrate / ammonium / sodium / chloride / water aerosols and that dissolved formate and acetate have negligible effect on the gas/aerosol equilibrium of the other components.     

Homogenous photocatalytic decomposition of acetic acid using UV-Fe/Fe system in the absence of oxygen

Photocatalysis is a promising way to eliminate organic pollution. Here a novel homogenous non-oxygen photocatalytic system was studied. Acetic acid was used as a model substrate to be decomposed into hydrogen, methane, ethane and carbon dioxide continuously by photo-excited Fe²⁺ and Fe³⁺ ions. Fluorescence spectra and ultraviolet visible spectra showed that Fe²⁺ and Fe³⁺ were excited by ultraviolet light. The rate of acetic acid decomposition increased along with the increase of temperature, Fe²⁺ and acetic acid concentration. The photocatalytic mechanism and kinetics were proposed and the effects of pH value, reaction temperature, concentration of FeSO₄ and CH₃COOH were investigated.     

Synthesis and characterization of low density and hydrophobic silica aerogels dried at ambient pressure using sodium silicate precursor

The present paper deals with the synthesis and characterization of low density and hydrophobic silica aerogels dried at ambient pressure using low cost sodium silicate precursor. The hydrogels were prepared by sol–gel processing of sodium silicate precursor and acetic acid catalyzed water followed by vapour passing and solvent exchange with methanol. The mixture of MeOH:trimethylchlorosilane (TMCS):hexane was used for the end capping of the silanols present on the silica surface. The process was optimized by varying vapour passing time, gel ageing time, molar ratios of H₂O/Na₂SiO₃, CH₃COOH/Na₂SiO₃ and TMCS/Na₂SiO₃ and silylation period. The aerogels have been characterized by bulk density, % of volume shrinkage, porosity, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis and contact angle measurements. The best quality silica aerogels in terms of low density (0.073 g/cc), higher porosity (96%) and better hydrophobicity (θ = 146°) have been obtained with the molar ratio of Na₂SiO₃:H₂O:CH₃COOH:TMCS at 1:166.6:2.25:11.9.     

A computational investigation into the nature of hydrogen bonds involving divalent sulfur

Factors contributing toward the hydrogen bond strength in the adducts of H₂S with model molecules H₂O, CH₃OH, HCOOH, CH₃COOH, H₂CO, (CH₃)₂O, NH₃, CH₃NH₂, HCONH₂, NH₂NH₂, HF and HCl have been studied. Various properties such as variation in geometrical parameters, atomic charge redistribution and alterations in conjugative interactions have been explored to rationalize the hydrogen bond acceptor and donor ability of S and S?H, respectively. NBO and SAPT analysis reveals that the attractive interactions resulting from electrostatic, inductive and dispersive interactions in adducts of H₂O have an edge over those in adducts of H₂S with a few exceptions and that all the components are affected by the nature of the H-bond donor and acceptor group in a similar manner in both the series of adducts, however the effect is different quantitatively.     

Metal-free mild oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

The potential of 4-hydroxy-2,2,6,6-tetramethyl-piperidine-1-oxyl (4-hydroxy-TEMPO radical) as an oxidant with [bis(acetoxy)-iodo]benzene (BAIB) and acetic acid (CH₃COOH) as co-oxidants to convert 5-hydroxymethylfurfural (5-HMF) into 2,5-diformylfuran (2,5-DFF) was investigated. The effects of oxidant/acid dosages, choice of appropriate solvent, reaction temperature and time were determined to maximize the 2,5-DFF yield. Optimally, 66% 2,5-DFF yield was achieved in TEMPO/BAIB/CH₃COOH system at 30 °C after 45 min in ethyl acetate. The reaction system is environmentally benign (metal-free) and energy efficient (mild at short reaction period). With scarce reports on 2,5-DFF production, the developed system provides an alternative route for a better access and wider application of this important platform chemical.     

Efficient extraction of impurities from phosphogypsum during crystal regulation of α-hemihydrate gypsum

Phosphogypsum (PG) is a solid waste generated during the “wet phosphoric acid process.” The phosphorus (P) impurities and low-value-added recycling products seriously constrain PG re-utilization, which results in its massive accumulation and thus occupies large land areas and poses a severe pollution threat to the environment. In this study, by regulating gypsum crystal and P species in CaCl₂–HCl solutions under mild conditions, efficient removal of P impurities (leaching efficiency of 97.78%) and synchronous preparation of high-strength α-CaSO₄·0.5H₂O (α-HH) (compressive strength of 35.2 MPa) from PG were achieved during the phase transition from CaSO₄·2H₂O (DH) to α-HH, which was a reaction of DH dissolution, followed by α-HH crystallization. The co-crystalline P was fully released during the dissolution process, which was necessary to efficiently eliminate P impurities. HCl dissolved the released P and transformed them into the protonated specie (H₃PO₄) with less similarity to SO₄²⁻, which prevented the recombination of the released P with gypsum during the crystallization process. Furthermore, α-HH morphology and size were controlled by seeding in the mixed solutions. The formation of regular large α-HH crystals with a low-specific surface area significantly weakened the surface adsorption of P in solutions and further increased the P leaching efficiency. More importantly, the large stumpy α-HH was identified as high-strength gypsum with high added value. This work would provide innovative guidance to efficiently remove impurities from gypsum and pioneer a cost-effective approach for clean and high-value utilization of industrial gypsum residues.     

冶金法制备太阳能硅过程的湿法提纯研究

湿法提纯作为冶金法路线制备太阳能级硅的前处理工序,可以去除大部分金属杂质,提高最终产品收率。考察了硅粉粒径、浸出剂浓度、温度、时间、搅拌等因素的影响,采用ICP、SEM等对产品进行了表征。当工艺条件为:硅粉平均粒径44μm、w(HCl)=5%、温度80℃、时间6h,处理后产品中杂质w(Fe)=2.4×10-5,去除率为99.2%,杂质w(Al)=6.4×10-5,去除率为80%。描述了酸浸过程在前后不同阶段分别为受反应速度和内扩散控制历程。为太阳能级硅制备工业化开发,大幅度降低成本提供了参考。     

Mesh-capped probe design for direct pH measurements at an actively corroding metal surface

Quantitative characterization of surface reaction species improves understanding of reaction mechanisms, especially for heterogeneous reactions such as in corrosion and electrolysis. A universal mesh-capped surface pH probe was developed in order to investigate surface proton concentrations for aqueous metal dissolution/deposition reactions. This technique can be generally applied to characterize the surface pH either for bare metal reactions or metals corroding beneath a corrosion product film. Measurements with the new probe design have shown a good degree of reproducibility. The surface pH measurements during corrosion of mild steel have shown that a higher surface pH is achieved at the steel surface as compared with that of the bulk solution, just as predicted from theory. Chemical buffering effects on surface pH were observed during corrosion by contrasting the measurements obtained in HCl deaerated solutions with those containing CO₂, i.e., carbonic acid (H₂CO₃) and acetic acid (CH₃COOH/HAc) solutions. It was found that the surface pH was mainly controlled by the water chemistry and chemical buffer capacity. The surface pH is affected by the deposited corrosion scale porosity. A higher deviation of surface pH compared to the bulk value was observed for more dense layers with lower porosity.