Adsorption of acid and basic dyes on NiO-SiO2 composites

A series of composites containing 2.5–21.0% NiO on a surface of macroporous silica is synthesized. The specific surface area of the composites measured by the thermal desorption of nitrogen decreases with an increase in the NiO content from 24 for the original silica carrier to 16 m²/g the for composite containing 21.0% NiO. The basic dye, methylene blue (MB), is only adsorbed on SiO₂ in water solutions, while acid blue anthraquinone (ABA) is only adsorbed on the NiO. The effective specific surface area Seff and effective diameters D _eff of NiO nanoparticles are calculated from the adsorption isotherms of ABA on NiO composites and on NiO synthesized without a carrier. S _eff of NiO nanoparticles decreases from 76 to 42 m²/g and D _eff increases from 8 to 14 nm with rising NiO content in the composites. The NiO nanoparticles synthesized without a carrier are characterized by the lowest S _eff (30 m²/g) and the largest D _eff (20 nm).     

A polysaccharide composite for water treatment to remove nitrates: Synthesis,properties, and utilization

A sorbent for water treatment to remove nitrates was prepared from readily available vegetable boipolymers: cellulose and starch. The adsorption characteristics of the polysaccharide composite were determined. Biodegradation of the spent composite in the course of its utilization was studied.     

Spectrophotometric determination of thorium as molybdothoric acid with basic dyes

Color developments based on the ion-association complexes of molybdothoric acid with three basic dyes (BD), rhodamine B(RB), butylrhodamine B(BRB) and nile blue (NB), were investigated in aqueous acidic solution in the presence of poly(vinyl alcohol) (PVA). Their spectrophotometric behavior, such as the conditions suitable for the reactions and the effects of foreign ions, were thoroughly studied. The ThMoBD ratio in the complexes was found to be 1123. Their absorption maxima were at 570, 570 and 590 nm with apparent molar absorptivities of 3.50 × 10^–6, 3.63 × 10⁶ and 4.45 × 10⁶ dm³ mol^–1 cm^–1, respectively. Beer's law was obeyed up to 0.8, 0.8 and 0.7 g thorium per 25 ml, respectively. The detection limits (3) were 1.1, 1.8 and 3.4 ng ml^–1, respectively, and for 0.02 ug ml^–1 solution of thorium the relative standard deviations were 3.0, 2.9 and 1.5%, respectively (n = 11). The proposed methods were applied to the determination of trace amounts of thorium in some geological samples.     

Wastewater purification to remove dyes with monocation-substituted forms of bentonite and flocculants-coagulants

Possibility of performing sorption-coagulation purification of model wastewater to remove cationactive dyes (Rhodamine G, Methylene blue, thionine, and fuchsine) with bentonite sorbents and Gyanja flocculant-coagulant was studied. The effect of the nature and charge of exchange cations on the sorptioncoagulation capacity of bentonite samples was examined.     

Image formation by dyeing of copolymers bearing photogenerated acid and base groups with dye bath containing acid and basic dyes

Copolymers bearing photoacid generating groups and/or photobase generating groups were dyed after UV irradiation with a dye bath containing both an acid dye and a basic dye. Acetophenone O‐acryloyloxime (AAPO) was used as a monomer bearing acyloxyimino (AOI) group that generates a primary amino group upon irradiation, which is followed by hydrolysis. Phenacylsulfonylstyrene (PSSt) and 1,2,3,4‐tetrahydronaphthylideneamino p‐styrenesulfonate (NISS) were chosen as monomers having β‐keto sulfone (β‐KS) and iminosulfonate (IS) groups, respectively, which yielded acid groups when irradiated. Copolymers of AAPO and methyl methacrylate (MMA) were dyed with only the acid dye, and those of PSSt or NISS were dyed with only the basic dye after irradiation. AAPO‐PSSt‐MMA films became dyeable with the acid dye when irradiated for a short time and with the basic dye with further irradiation. However, AAPO‐NISS‐MMA copolymers showed the reverse dyeing behavior. IR spectra revealed that AOI groups were photochemically decomposed prior to the β‐KS groups for AAPO‐PSSt‐MMA, and AOI and IS groups decomposed simultaneously for AAPO‐NISS‐MMA. These results suggested the possibility of adsorption of different ionic dyes on the films by a change of irradiation time; in fact, color patterns could be obtained in a single staining process using the dye bath. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3043–3051, 2000     

Kinetic modeling of the adsorption of basic dyes by kudzu

The use of kudzu, a rapidly growing, high-climbing perennial leguminous vine, for the adsorption of basic dyes from aqueous solution has been investigated at various initial dye concentrations, masses of kudzu, and agitation rates. The extent and rate of adsorption of the three basic dyes (Basic Red 22, Basic Yellow 21, and Basic Blue 3) were analyzed using a pseudo-first-order and a pseudo-second-order kinetic model. While both rate mechanisms provided an acceptable degree of correlation with the experimental sorption rate data, the pseudo-second-order model gave a much higher degree of correlation, suggesting that this model could be used in design and simulation applications.     

Encapsulation of diagnostic dyes in the polysaccharide matrix modified by carbon nanotubes

The effect of carbon nanotubes (CNTs) on the morphology and properties of alginate hydrogel was studied. The addition of CNTs leads to a change in the structural characteristics of the hydrogel, which is expressed in a decrease in the pore size and gaining a more uniformity by the internal structure. To study the encapsulating properties of the designed compositions, a set of dyes was used that are traditionally applied for testing the drug release rate. It was found that the CNTs do not affect the efficiency of inclusion and the release rate of the anionic and neutral dyes. The change in the kinetics of cationic dye release is caused by the reinforcing effect of the CNTs on the alginate hydrogel and a change in its morphological characteristics.

     

Ion-selective electrodes based on tetraphenyl-phosphonium 12-tungstosilicate and on crystal violet tetraphenylborate in the potentiometric titration of acid and basic dyes

Poly(vinyl chloride) membrane electrodes containing the specified substances are suitable as indicator electrodes in titrations of basic dyes with sodium tetraphenylborate solution and of acidic dyes with crystal violet solution. Useful curves are obtained even at the 10^-3 M level.     

Nanofiltration treatment of aqueous solutions to remove triazine herbicides

Nanofiltration treatment of aqueous solutions to remove triazine herbicides (terbumetone, desmetrine, atrazine) with an OPMN-P membrane was studied. The effect of the molecular mass of herbicides, working pressure, and extent of permeate removal on the retention of solutes was analyzed.     

Wastewater treatment with new activated charcoals to remove butanol

Adsorption of butanol under static conditions on two types of activated charcoals, prepared from birch and a blend of oak and beech, was studied. The adsorption on birch charcoal was carried out under dynamic conditions. The limiting stage of the process was determined. The dependence of the purification efficiency on the fractional composition of activated charcoal and the feed rate of the contaminated solution was studied. The regeneration of birch charcoal with steam and by calcination was performed.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1525–1527.Original Russian Text Copyright © 2004 by Krivosheev, Komarova, Poletaeva, Lebedev, Lavrinenko.     

Enantioseparations of basic and bifunctional pharmaceuticals by capillary electrochromatography using polysaccharide stationary phases

A fast screening strategy was developed in capillary electrochromatography (CEC) for the chiral separation of basic and bifunctional compounds. The screening conditions were determined on polysaccharide chiral stationary phases using 15 pharmaceutical compounds. The content and type of organic modifier, as well as the pH of the mobile phase appeared to have the largest influence on the chiral resolution. It was seen that for acidic compounds, our approach was not suitable. A generic mobile phase for basic and bifunctional compounds was determined. The testing on 20 additional compounds showed that the proposed mobile phase performed well since enantioselectivity was observed for 86% of the investigated compounds. A comparison of CEC and reversed-phase liquid chromatography (RPLC) results was attempted to demonstrate the potential of the used technique for chiral method development.     

Analysis of basic hair dyes by HPLC with on-line post-column photochemical derivatisation

Summary A reversed phase liquid chromatographic method is proposed for the analysis of basic hair dyes (raw materials and colourant formulations). The performance of the method was enhanced by introducing post-column on-line photochemical derivatisation in combination with a Diode Array Detector. On-line photoderivatisation provided an effective way of selectively transforming the analytes to compounds with different spectral properties. For each analyte two characteristic UV-Visible spectra (photoreactor on and off) were obtained with the same mobile phase and this information in combination with the chromatographic data (k' at pH 3.0 and 4.5) enabled the unambiguous identification of both commonly used, approved, and banned basic hair dyes. Additionally, this approach was found useful to improve the method sensitivity, allowing the determination of analytes present in low concentration (0.03%) in complex commercial formulations.This work constitutes part of the thesis for the Dottorato di Ricerche of Roberto Gotti.     

Squaraine dyes in PDT: from basic design to in vivo demonstration

The design and development of novel squaraine dyes as sensitisers for photodynamic therapy (PDT) applications has grown tremendously in the last decade from the time when a squaraine dye was proposed to be a potential candidate, to-date when the use of such dyes have been demonstrated in animal models for skin cancer. This perspective article highlights the basic design, tuning of absorption, triplet excited state and two-photon absorption properties and recent developments of the squaraines as PDT sensitisers.     

Separation and determination of basic dyes formulated in hair care products by capillary electrophoresis

A capillary electrophoretic (CE) method for analyzing five basic dyes (Basic Red 76, Basic Brown 16, Basic Yellow 57, Basic Brown 17 and Basic Blue 99) sold under the trade name Arianor, which are commonly used in hair care products, has been established. A buffer of 100 mM acetic acid-ammonium acetate (50:50) containing 90% (v/v) methanol was employed in a fused-silica capillary of 40.0 cm x 50 microm I.D. with a bubble cell arrangement. Washing the capillary end immediately after injection was effective in preventing peak tailing of the basic dyes, which was due to their adsorption onto the outer wall of the capillary during the injection. Under these optimized conditions, acceptable results for reproducibility, limit of detection and quantitation, and linearity were obtained for the five authentic dyes tested. The recoveries of five authentic basic dyes spiked to three commercial hair care products also provided with acceptable results. This optimized CE method is useful for the analysis of mixed basic dyes in hair care products.     

Determination of inorganic salts in acid and direct dyes by chromatography on polyamide

Summary A method for the determination of the inorganic salts content (Na₂SO₄, NaCl) in acid and direct dyes has been developed. The solution of the dye is introduced into a column filled with a strong acid cation exchanger and elution is carried out with water. The dye is converted to its free acid and the eluate is allowed to pass through a second column filled with polyamide. The free dye acid is adsorbed and the whole content of chloride and sulphate appears in the first 150 ml of the eluate. The determination of both chloride and sulphate is carried out gravimetrically using common methods.With this procedure inorganic salt contents up to 60% can be determined with an accuracy of ±2.0% rel.

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Bestimmung von anorganischen Salzen in sauren und Direkt-Farbstoffen durch Chromatographie an Polyamid

Zusammenfassung 20 ml der wÄ\rigen Lösung mit 50 mg des Farbstoffes werden auf eine 120×8 mm SÄule eines stark sauren Kationenaustauschers (Ostion LG-KS) in H⁺-Form aufgetragen und mit Wasser eluiert. Das Eluat wird auf eine 120×8 mm SÄule von Polyamidpulver gegeben, wobei der Farbstoff adsorbiert wird. In 150 ml des Eluats sind dann die anorganischen Salze (Na₂SO₄, NaCl) enthalten. Sulfat sowie Chlorid werden am besten gravietrisch nach üblichen Methoden bestimmt.Auf diese Weise können die anorganischen Salze bei einem Gehalt bis zu 60 % mit einer Genauigkeit von ±2,0% rel. bestimmt werden.

     

Barrier-discharge plasma treatment of surface water to remove organic compounds

Barrier-discharge plasma treatment of real surface water to remove organic pollutants was studied. Plasma treatment decreases the potential toxicity of snowmelt and rainfall runoff containing ammonium and chloride ions, oil products, phenols, and carboxylic acids (as recalculated for CH₃COOH).     

A biosorption isotherm model for the removal of reactive azo dyes by inactivated mycelia of Cunninghamella elegans UCP542

The biosorption of three reactive azo dyes (red, black and orange II) found in textile effluents by inactive mycelium of Cunninghamella elegans has been investigated. It was found that after 120 hours of contact the adsorption led to 70%, 85%, 93% and 88% removal of reactive orange II, reactive black, reactive red and a mixture of them, respectively. The mycelium surface was found to be selective towards the azo dyes in the following order: reactive red > reactive black > orange II. Dye removal from a mixture solution resulted in 48.4 mg/g retention by mycelium and indicated a competition amongst the dyes for the cellular surface. A Freundlich adsorption isotherm model exhibited a better fit, thus suggesting the presence of heterogeneous binding sites. Electrondense deposits observed on the mycelium ultrastructure suggest that the dyes are mainly retained under the cellular surface of the inactive biomass of C. elegans.     

反相离子对色谱法对两种新型苯磺酸类染料中间体的研究

用ZorbaxSBC18柱对2 氨基 4 氯 5 甲基苯磺酸和4 氨基 5 甲氧基 2 甲基苯磺酸两种新型染料中间体进行了反相离子对色谱法的研究。以甲醇和2mmol L四丁基溴化铵,5mmol L磷酸二氢钠溶液为流动相,紫外检测波长215nm。可在15min内对这两种染料中间体分别进行杂质检测和纯度分析。线性范围均为0.2～2.0μg,回归方程分别为Y=648.3 71.2ρ,r=0.9995;Y=177.3 65.0ρ,r=0.9994。该方法可用于对这两种染料中间体产品质量的监控及产品真伪的辨别。