Design of PAMAM grafted chitosan dendrimers biosorbent for removal of anionic dyes: Adsorption isotherms, kinetics and thermodynamics studies.

PAMAM grafted chitosan as biocompatible adsorbent was synthesized through Michael addition of methyl acrylate followed by amidation of ethylenediamine on the chitosan backbone. Then, the adsorption capacity of bioadsorbents were assessed by employing two anionic dyes. The adsorption experiments were carried out using a batch adsorption system. The influence of various operational variables such as different PAMAM generations, pH, adsorbent dosage, contact time, initial dye concentration and temperature on the maximum adsorption capacity (qm) were investigated. The adsorbent consists of second generation of PAMAM (CS-PAMAM G2) demonstrated high removal efficiency for both dyes. The maximum adsorption capacity of CS-PAMAM G2 for Congo Red at certain operational conditions was 559.3 mg/g; while the maximum adsorption capacity for Amido Black 10B at certain operational conditions was 489.8 mg/g; which revealed endothermic and exothermic nature of adsorption process for Congo Red and Amido Black 10B, respectively. These results were then well confirmed by thermodynamics studies. Also, kinetic studies showed that the dye adsorption process followed a pseudo-second-order kinetic model. Moreover, among various applied isotherms, the experimental data were well-fitted by Sips model. Consequently, CS-PAMAM G2 showed superior potential for the removal of dyes from aqueous phase.

The investigation of Amido black 10B adsorption-photocatalytic degradation using the synergistic effect of Cr-doped ZnO/CDs nanocomposite under solar light.

In this work, the modification of ZnO nanoparticles with green synthesized carbon dots and Cr yielded a nanocomposite named Cr-doped ZnO/CDs. Further, 0.48 g/L of this nanocomposite was able to remove (95 ± 1) % of 25 mg/L Amido black 10B (AB10B) from a solution, by adsorption process less than 5 min. The photocatalytic property of Cr-doped ZnO/CDs was able to improve the removal efficiency of AB10B to 99% during irradiation of sunlight within 15 min. The maximum adsorbent capacity of Cr-doped ZnO/CDs nanocomposite was 152.4 mg/g. Unmodified ZnO nanoparticles (0.48 g/L) were able to remove only 30% of the dye within 60 min of irradiation. Its modification showed coupling the absorption and photocatalytic process dramatically increased the dye removal efficiency. Adsorption isotherm investigation indicated that the experimental data were fitted satisfactorily by the Langmuir model. This method is an economical method because the Cr-doped ZnO/CDs synthesis was easy and inexpensive, the dye removal time was very short, and infinite sunlight is required to remove the dye with high efficiency. Graphical abstract.

Immunoelectrophoresis: A Method with Many Faces.

Immunoelectrophoresis (IEP) was the first practical method that combined electrophoresis and immunoprecipitation for identifying and characterizing proteins within complex mixtures. Over the years, IEP has been extended to include a variety of techniques and, as a general name, has been applied to virtually any technique that involves electrophoresis and antigen-antibody precipitin reaction for proteins. Because of the diversity in technical details of different IEP versions, the method described here deals only with classic IEP. Although it requires some manual expertise, IEP is versatile, relatively easy to customize, and economical with no need for expensive instrumentation. Further, it can discern identity, partial identity, and nonidentity of the proteins. Any low-viscosity body fluid specimen or, possibly, culture fluid and tissue extract could be tested with IEP if proper antibodies are available. With these attributes, classic IEP remains a valuable tool for clinical diagnostic testing, purity checking of biochemical and pharmaceutical products, and research.

Measuring Protein Concentration on Nitrocellulose and After the Electrophoretic Transfer of Protein to Nitrocellulose.

Proteins bind to nitrocellulose membranes when applied directly or after electrophoretic transfer from polyacrylamide electrophoresis gels. Proteins can be stained for visualization with organic dyes Ponceau S, amido black, Coomassie Blue, and colloidal silver/gold and the intensity of the stain is directly proportional to the amount of protein present. Chemicals that interfere with dye/protein interactions in solution can be removed by washing the nitrocellulose after protein application. A method is described whereby protein-dye complexes attached to the nitrocellulose can be solubilized, dissolving the nitrocellulose and releasing dye into solution for detection by a spectrophotometer. The concentration of the dyes Ponceau S, amido black, and colloidal silver is proportional to the concentration of protein. Proteins transferred electrophoretically from SDS-PAGE, isoelectric focusing, or 2D gels to nitrocellulose can be stained with amido black, protein bands excised, and the bound dye detected in a spectrophotometer to quantify proteins in the individual protein bands.

Protein Stains to Detect Antigen on Membranes.

Western blotting (protein blotting/electroblotting) is the gold standard in the analysis of complex protein mixtures. Electroblotting drives protein molecules from a polyacrylamide (or less commonly, of an agarose) gel to the surface of a binding membrane, thereby facilitating an increased availability of the sites with affinity for both general and specific protein reagents. The analysis of these complex protein mixtures is achieved by the detection of specific protein bands on a membrane, which in turn is made possible by the visualization of protein bands either by chemical staining or by reaction with an antibody of a conjugated ligand. Chemical methods employ staining with organic dyes, metal chelates, autoradiography, fluorescent dyes, complexing with silver, or prelabeling with fluorophores. All of these methods have differing sensitivities and quantitative determinations vary significantly. This review will describe the various protein staining methods applied to membranes after western blotting. "Detection" precedes and is a prerequisite to obtaining qualitative and quantitative data on the proteins in a sample, as much as to comparing the protein composition of different samples. "Detection" is often synonymous to staining, i.e., the reversible or irreversible binding by the proteins of a colored organic or inorganic chemical.

Porous chitosan doped with graphene oxide as highly effective adsorbent for methyl orange and amido black 10B.

In the current study, porous chitosan aerogels doped with small amount of graphene oxide (CSGO aerogels) with high porosity (97.96-98.78%), extraordinarily high water absorption (5848-8917%) and low density (0.021-0.035 g cm(-3)) were prepared and used as adsorbents for two azo dyes methyl orange (MO) and amido black 10B (AB10B). The adsorption behavior of these CSGO aerogels and some influence factors such as pH value, graphene oxide (GO) loading, concentration of pollutants, as well as adsorption kinetics were studied. Specifically, the adsorption capacity for MO is 686.89 mg g(-1), the highest comparing with other publication results, and it is 573.47 mg g(-1) for AB10B. Since they are biodegradable, non-toxic, efficient, low-cost and easy to prepare, we believe that these porous CSGO aerogels will be a promising candidate for dye removal.

A modified protein assay from microgram to low nanogram levels in dilute samples.

In this article, we present a modified and improved protein assay that was previously described as "amidoschwarz assay" by Schaffner and Weissmann. Our improved protein assay is user-friendly and 30-40 times more sensitive than the earlier method. The assay was developed into three formats (macro-, micro-, and nanoassay) with trichloroacetic acid (TCA) as protein precipitating agent, measuring up to 96 samples. The macro and micro formats of this assay require a single reagent staining with amido black of protein dots bound to nitrocellulose membrane with lowest protein measurements to 1 and 0.1 µg, respectively. On the other hand, the nanoassay, with combination staining of amido black followed by colloidal gold, can extend the detection limit to 2.5 ng of protein. Protein concentrations were determined by densitometry and/or spectrophotometry. This assay is compatible with many ionic and non-ionic detergents. This improved protein assay provides an additional choice to researchers in measuring total protein concentration accurately in dilute biological samples as low as 0.125 µg/ml prior to their biochemical analysis such as in comparative proteomics.

Accelerated azo dye removal by biocathode formation in single-chamber biocatalyzed electrolysis systems.

Biocatalyzed electrolysis systems (BES) have been the topic of a great deal of research. However, the biocathodes formed in single-chamber BES without extra inocula have not previously been researched. Along with the formation of biocathodes, the polarization current increased to 1.76 mA from 0.35 mA of abio-cathodes at -1.2 V (vs. SCE). Electrochemical impedance spectroscopy (EIS) results also indicated that the charge transfer resistance (Rct) was decreased to 148.9 Ω, less than 1978 Ω of the abio-cathodes cleared. The performance of the biocathodes was tested for azo dye decolorization, and the dye removal efficiency was 13.3±3.2% higher than abio-cathodes with a 0.5 V direct current (DC) power supply. These aspects demonstrate that biocathode accelerates the rate of electrode reaction in BES and comparing with noble metal catalysts, biocathodes have low toxicity or non-toxic and reproducible properties, which can be widely applied in bioelectrochemical field in the future.

Ag2S-ZnO--an efficient photocatalyst for the mineralization of Acid Black 1 with UV light.

The Ag(2)S loaded ZnO (Ag(2)S-ZnO) was successfully synthesized by precipitation of zinc oxalate and Ag(2)S and calcination of the mixed precipitate at 400 °C for 12 h. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) images, energy dispersive spectra (EDS), diffuse reflectance spectra (DRS) photoluminescence spectra (PL) and BET surface area measurements. The photocatalytic activity of Ag(2)S-ZnO was investigated for the degradation of Acid Black (AB 1) in aqueous solution using UV light. Ag(2)S-ZnO is found to be more efficient than commercial ZnO, prepared ZnO and TiO(2)-P25 at pH 9 for the mineralization of Acid Black 1. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization have been analyzed. Mechanism of degradation by Ag(2)S-ZnO is proposed. The mineralization of Acid Black 1 has also been confirmed by COD measurements. The catalyst is found to be reusable.

Adsorptive removal of toxic azo dye Amido Black 10B by hen feather.

UNLABELLED: PURPOSE AND AIM: Amido Black 10B is an azo dye with very high toxicity. It is now established that the dye damages the reparatory system of humans and also causes skin and eye irritations. It is therefore considered worthwhile to develop a systematic procedure to eradicate Amido Black 10B from its aqueous solution using a waste material as adsorbent. Therefore, adsorption of the dye is achieved using hen feathers as adsorbent. MATERIALS AND METHODS: Before using hen feather as adsorbent material, it is washed, cut into small pieces and activated using hydrogen peroxide. Detailed chemical and physical analysis of hen feather was also carried out by known analytical techniques. The adsorptive removal of the dye was made through batch experiments in 100 mL airtight flasks. The experiment is divided in three major categories, the preliminary investigations, adsorption isotherm measurements, and kinetic studies. RESULTS: Under preliminary investigations, the effect of pH, temperature, concentration of dye, and amount of adsorbent were carried out. It was found that with increase in pH, the adsorption of Amido Black 10B decreases; while with increasing the amount of hen feather, it increases. The isothermal studies indicate that the ongoing adsorption process is endothermic in nature and obeys Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevitch (D-R) adsorption isotherm models. The Gibb's free energy and entropy of the adsorption were also calculated. The D-R isotherm model verified the involvement of chemisorption during the adsorption. The kinetic measurements indicate operation of pseudo second order process during the adsorption and dominance of film diffusion mechanism at all the temperatures. CONCLUSIONS: The developed method is highly efficient and ecofriendly. It also ascertains a necessitous utilization of waste material hen feather for the benefit of the society.

Removal of organic dyes by UV/H2O2 process: modelling and optimization.

The effects of different operational parameters on the decolorization of a dye solution containing C.I. Acid Blue 92 (AB92) or C.I. Acid Black 1 (AB1) by the UV/H2O2 process were optimized using response surface methodology (RSM). The reaction time, dye and H2O2 initial concentrations and distance of the UV lamp from the solution were chosen as input variables. The removal process was performed according to a central composite design. Predicted results by the proposed models were in good agreement with experimental values (R2 = 0.942 and 0.957 for AB92 and AB1, respectively). The optimum points were located by graphical response surfaces and contour plots. The removal process of the dyes was compared and the efficiency difference justified by considering the chemical structure of the dyes. Additionally, the electrical energy consumption and the related treatment costs were estimated employing the figure-of-merit electrical energy per order (E(EO)).

Immunofixation electrophoresis for identification of proteins and specific antibodies.

Immunofixation electrophoresis (IFE) is a technique for the identification of proteins within complex mixtures after separation by either conventional zone electrophoresis or isoelectric focusing. Most commonly antigens (which are often immunoglobulins) are separated by electrophoresis followed by precipitation with specific antibodies in situ. However, immunoglobulins with specific reactivity can be also precipitated with the proper antigens after electrophoresis in reverse or reversed IFE. Because of its great versatility, potentially high sensitivity, ease to perform and customize, and relatively low cost with no requirement for expensive instrumentation, manual IFE remains a valuable tool for both clinical diagnostic testing and research. Any low-viscosity body fluid specimen or, possibly, culture fluid could be tested with IFE if proper antibodies (or antigens in reverse[d] IFE) are available. After pretreatment with chaotropic and/or reducing agents, even high-viscosity specimens might be amenable to testing with IFE.

Immunoelectrophoresis: a method with many faces.

Immunoelectrophoresis (IEP) was the first practical method that combined electrophoresis and -immunoprecipitation for identifying and characterizing proteins within complex mixtures. Over the years, IEP has been extended to include a variety of techniques and, as a general name, has been applied to virtually any technique that involves electrophoresis and antigen-antibody precipitin reaction for proteins. Because of the diversity in technical details of different IEP versions, the method described here deals only with classic IEP. Although it requires some manual expertise, IEP is versatile, relatively easy to customize, and economical with no need for expensive instrumentation. Further, it can discern identity, partial identity, and nonidentity of the proteins. Any low-viscosity body fluid specimen or, possibly, culture fluid and tissue extract could be tested with IEP if proper antibodies are available. With these attributes, classic IEP remains a valuable tool for clinical diagnostic testing, purity checking of biochemical and pharmaceutical products, and research.

Rapid detection of proteins in polyacrylamide electrophoresis gels with Direct Red 81 and Amido Black.

Proteins separated by SDS-polyacrylamide gel electrophoresis need to be stained with organic dyes to be visualized and to enable comparisons to be made between the intensity of protein bands to observe and determine differences in protein concentration. The standard protein staining is with Coomassie Blue R-250. Coomassie staining takes 1 h to complete. Direct Red 81 and Amido Black stain proteins within 10 min. This chapter describes Direct Red 81 and Amido Black staining in comparison to staining with Coomassie Blue R-250.

Adsorptive removal of an acid dye by lignocellulosic waste biomass activated carbon: equilibrium and kinetic studies.

Chemically prepared activated carbon material derived from palm flower was used as adsorbent for removal of Amido Black dye in aqueous solution. Batch adsorption studies were performed for the removal of Amido Black 10B (AB10B), a di-azo acid dye from aqueous solutions by varying the parameters like initial solution pH, adsorbent dosage, initial dye concentration and temperature with three different particle sizes such as 100 µm, 600 µm and 1000 µm. The zero point charge was pH 2.5 and the maximum adsorption occurred at the pH 2.3. Experimental data were analyzed by model equations such as Langmuir, Freundlich and Temkin isotherms and it was found that the Freundlich isotherm model best fitted the adsorption data and the Freundlich constants varied from (K(F)) 1.214, 1.077 and 0.884 for the three mesh sizes. Thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated for the adsorption processes and found that the adsorption process is feasible and it was the endothermic reaction. Adsorption kinetics was determined using pseudo first-order, pseudo second-order rate equations and also Elovich model and intraparticle diffusion models. The results clearly showed that the adsorption of AB10B onto lignocellulosic waste biomass from palm flower (LCBPF) followed pseudo second-order model, and the pseudo second-order rate constants varied from 0.059 to 0.006 (g mg(-1)min) by varying initial adsorbate concentration from 25 mg L(-1) to 100 mg L(-1). Analysis of the adsorption data confirmed that the adsorption process not only followed intraparticle diffusion but also by the film diffusion mechanism.

Comparative analysis of bioremediation potential of adapted and non-adapted fungi on azo dye containing textile effluent.

About 4 different predominant adapted fungal strains (screened from effluent sample) Aspergillus sp., Penicillium sp., Fusarium sp. and Mucor sp. and 4 predominant non-adapted strains (screened from soil, water and fungal fruiting bodies) Aspergillus sp., Penicillium sp., Fusarium sp. and Rhizopus sp., with potential dye decolorization ability on Reactive black 5, Amido black-10B, Red 5B, Reactive red 120 and Anthraquinone violet R were isolated. These organisms were used to develop a consortium which was used in analyzing the bioremediation efficiency on textile effluents containing a mixture of azo dyes. There was about 67% of reduction in color along with 34% of COD reduction by non-adapted fungal consortium while effective bioremediation efficiency was observed in adapted fungal consortium (Color 75% and COD 50%). The regression co-efficient for Langmuir and Freundlich adsorption isotherms were found to be higher for adapted fungal consortium (R2 = 0.97 and R2 = 0.92) than the non-adapted consortium (R2 = 0.97 and R2 = 0.85) proving that both monolayer and multilayer adsorption of dyes were observed on treating the samples with the adapted fungal consortium. On analyzing the results observed through chi-square test, the calculated value (28.712) was higher than the tabulated value (9.49) at a 4 degree freedom hence the hypothesis was rejected. So, there was an association between adapted fungal consortium and non-adapted fungal consortium and hence the adapted fungal consortium could be considered potentially useful for the bioremediation of textile effluent.

Liquid chromatography tandem mass spectrometry analysis of photodegradation of a diazo compound: a mechanistic study.

The photolytic degradation of the diazo dye, Amido Black, using UV/H(2)O(2) has been carried out experimentally and parameters for most efficient dye degradation have been determined. The degradation of the dye was followed by UV-Vis spectroscopy, HPLC, and LC-MS and is proposed to be initiated by ()OH radicals formed by the photolysis of H(2)O(2). A detailed study was also carried out using LC-MS and LC-MS/MS to determine the degradation pathway of the dye as well as to identify some of the intermediate products formed. Our results suggest that Amido Black degradation occurs preferentially by ()OH radical attack at the more electron rich diazo functionality of the molecule. Furthermore, evidence is presented that subsequent steps in this diazo dye degradation pathway include radical denitration, radical desulfonation and radical diazotization. This report is one of the very few studies that have proposed possible mechanistic pathways for the degradation pathways of a diazo compound.

Direct red 81 and amido black stain proteins in polyacrylamide electrophoresis gels within 10 min.

Proteins separated by SDS-polyacrylamide gel electrophoresis can be stained with organic dyes, the most popular being Coomassie brilliant blue R-250. Coomassie R-250 staining of ovalbumin in an SDS-PAGE gel increased linearly from 2.5 to 60 min. Direct red 81 and amido black staining approached saturation in 10 min. Scatchard analysis showed that the number of direct red 81 and amido black ligands bound to ovalbumin was fourfold higher than that of Coomassie R-250. Direct red 81 and amido black stain proteins in an SDS-polyacrylamide electrophoresis gel in 10 min.

Mass spectrometry-compatible silver staining of histones resolved on acetic acid-urea-Triton PAGE.

Acetic acid-Urea-Triton (AUT) PAGE is commonly used method to separate histone variants and their post-translationally modified forms. Coomassie staining is the preferred method for protein visualization; however, its sensitivity is less than that of silver staining. Though silver staining of histones in AUT-PAGE has been reported, the method is time-consuming, dependent on prior staining by Amido black and has not been reported suitable for mass spectrometry. Here, we propose 'SDS-Silver' method for rapid, sensitive and mass spectrometry-compatible staining of histones resolved on AUT-PAGE.

Comparative study on the degradation of I.C. Remazol Brilliant Blue R and I.C. Acid Black 1 by Fenton oxidation and Fe 0/air process and toxicity evaluation.

Degradation of Remazol Brilliant Blue R (anthraquinone dye) and Acid Black 1 (azo dye) by Fenton oxidation and low-cost Fe(0)/air process was compared. The doses of Fenton reagent needed for decolorization of Remazol Brilliant Blue R was much higher than for Acid Black 1. The Fe(0)/air process rapidly decolorized dyes within 5 min at the Fe(0) doses of 10 and 50 g L(-1) for Remazol Brilliant Blue R and Acid Black 1, respectively. COD removals of Remazol Brilliant Blue R and Acid Black 1 by the Fe(0)/air treatment were significantly higher than those by Fenton oxidation. 98% COD of Remazol Brilliant Blue R was removed by the Fe(0)/air process. The toxicity of Fe(0)/air-treated solution was significantly lower than that of Fenton-treated solution; no toxicity was detected after the treatment of Remazol Brilliant Blue R by the Fe(0)/air process. Fe(0)/air technique is a potential process for dye degradation.