Decolorization Ratio Research Articles

Synthesis and properties of xanthan gum-acrylamide-carboxymethyl cellulose ternary anionic flocculants

Natural polymer based flocculants are prospective in water treatment on account of their advantages of wide source, simple operation process and ecological safety. However, its flocculation performance and cost effectiveness are usually not as satisfactory. In this work, xanthan gum-acrylamide-carboxymethyl cellulose (XAC) ternary anionic flocculant was synthesized with hydrothermal copolymerization. The polymerization conditions of raw material ratio, initiator dose, copolymerization time and reaction temperature were optimized by flocculation tests. The decolorization ratio of 82.9 % was obtained with XAC dosage of 35 mg/L for the 100 mg/L crystal violet aqueous solution. The as-prepared flocculants showed super decolorization ability and fast flocculation kinetics. The flocculation mechanism includes charge neutralization and bridging effects. More importantly, the operating expense of XAC is approximately 50 % of traditional polyacrylamide flocculant. In virtues of ecofriendliness, superior flocculation capacity and low expense, XAC flocculants show great promise for sewage treatment and open up a novel area for the natural polymer utilizations.

Nanocomposites from spent coffee grounds and iron/zinc oxide: green synthesis, characterization, and application in textile wastewater treatment.

This study reports on a novel composite of bimetallic FeO/ZnO nanoparticles supported by spent coffee grounds (SCGs). The leaves of eucalyptus (Eucalyptus globulus Labill) and trumpet (Cuphea aequipetala Cav), with their high antioxidant content, serve as bio-reductant agents for the green synthesis of nanoparticles. It was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Stable nanoparticles were produced with different diameters of 5-30 nm, and they were applied as catalysts in Fenton-like processes. Box-Behnken experimental design (BBD) was used to determine the optimal removal efficiency with three factors and was used in the degradation of textile dyes from wastewater. The nanocomposite displayed a high decolorization ratio (88%) of indigo carmine in the presence of H2O2 combined. This resulted in a reduction in chemical oxygen demand (COD) of 56% at 120 min of contact time at an initial pH of 3.0 and a 0.5 g/L of catalyst dose, a H2O2 concentration of 8.8 mM/L, an initial dye concentration of 100 mg/L, and a temperature of 25 °C.

Effect of Enhanced Hydrolytic Acidification Process on the Treatment of Azo Dye Wastewater.

The hydrolysis acidification process is an economical and effective method, but its efficiency is still low in treating azo dye wastewater. It is therefore crucial to find more suitable and efficient means or techniques to further strengthen the process of treating azo dye wastewater by a hydrolytic acidification process. In this study, a hydrolytic acidification aerobic reactor was used to simulate the azo dye wastewater process. The change of wastewater quality during the reaction process was monitored, and the deep enhancement effect of single or composite biological intensification technology on the treatment of azo dye wastewater by the hydrolytic acidification process was also explored. Co-substrate strengthening and the addition of fructose co-substrate can significantly improve the efficiency of hydrolytic acidification. Compared with the experimental group without the addition of fructose, the decolorization ratio of wastewater was higher (93%) after adding fructose co-substrate. The immobilization technology was strengthened, and the immobilized functional bacteria DDMZ1 pellet was used to treat the simulated azo dye wastewater. The results showed that the composite technology experimental group with the additional fructose co-matrix had a better decolorization efficiency than the single immobilized bio-enhancement technology, with the highest decolorization ratio of 97%. As a composite biological intensification method, the fructose co-matrix composite with immobilized functional bacteria DDMZ1 technology can be applied to the treatment of azo dye wastewater.

High performance, cost-effective and ecofriendly flocculant synthesized by grafting carboxymethyl cellulose and alginate with itaconic acid

Natural polymer flocculant possesses an exciting prospect in water treatment due to its non-toxicity, wide source, low cost and biodegradability. In this work, we have successfully synthesized the anionic terpolymer of carboxymethyl cellulose-itaconic acid‑sodium alginate (CIS) by microwave-assisted copolymerization. By studying the flocculation properties towards cationic dye of crystal violet (CV), the optimum synthesis conditions were determined. The maximum removal rate of 100 mg/L CV simulated wastewater was 92.2 % with CIS concentration of 30 mg/L. The flocculation kinetic results showed the rapid dye removal rate and the dye decolorization ratio of 89.8 % could be obtained at 75 s. Moreover, the CIS flocculant showed excellent flocculation effects in ambient pH of 4–10, flocculation temperature of 10–40 °C, and various inorganic salts. In general, the anionic CIS flocculant shows excellent cost effectiveness, where the predicted operation cost of as-prepared CIS is about 60 % of conventional polyacrylamide flocculant. It also has the advantages of excellent ecofriendliness and rich raw material source, indicative its potential applications of wastewater treatment.

Activation of peroxymonosulfate by catalysts derived from water treatment plant sludge for the simultaneous removal of Disperse Blue 56 and phosphates.

In this study, calcined water treatment plant sludge (C-WTPS) was used as a catalyst for peroxymonosulfate (PMS) activation to simultaneously remove Disperse Blue 56 (DB56) and phosphates. Firstly, the performance of the C-WTPS/PMS system was examined for the degradation of DB56. The results showed that 96.7% of DB56 (400mgL-1) was removed within 60min in the presence of 4.8gL-1 PMS and 0.8gL-1 C-WTPS at pH3 and 50°C. Hydroxyl radicals (·OH), sulfate radicals (SO4·-), and singlet oxygen (1O2) were generated during the oxidation process, and 1O2 was the main active species. The relatively high surface area, proper Fe content, and abundant ketone groups on the catalyst surface were responsible for PMS activation. Furthermore, the possible degradation pathways of DB56 were proposed based on the gas chromatography-mass spectrometry (GC-MS) results. Secondly, the simultaneous removal of DB56 and phosphates by the C-WTPS/PMS system was investigated. Due to the different removal mechanisms, the effects of the initial phosphate concentration and water matrix species on the removal of DB56 and phosphates showed different trends. Reusability tests results showed that C-WTPS had relatively high stability. In addition, the C-WTPS/PMS system exhibited a high decolorization ratio and phosphate removal efficiency in real wastewater tests. This article offers a value-added approach for reusing WTPS as a catalyst for treating organic contaminants and phosphates.

Preparation and Antioxidant Activity In Vitro of Fermented Tremella fuciformis Extracellular Polysaccharides

This study was aimed at increasing the capacity of fermented Tremella fuciformis extracellular polysaccharides (TEPS) for possible functional food applications. Thus, strain varieties, fermentation parameters and purification conditions, and the in vitro antioxidant activities of purified EPS fractions were investigated. An EPS high-yield strain Tf526 was selected, and the effects of seven independent fermentation factors (time, temperature, initial pH, inoculum size, shaking speed, carbon, and nitrogen source) on the EPS yield were evaluated. By single factor optimization test, yeast extract and glucose were chosen as nitrogen sources and carbon sources, respectively, and with initial pH of 6.0, inoculum size of 8%, shaking speed of 150 rpm, and culture at 25 °C for 72 h, the optimal yield of TEPS reached 0.76 ± 0.03 mg/mL. Additionally, A-722MP resin showed the most efficient decoloration ratio compared to six other tested resins. Furthermore, optimal decoloration parameters of A-722MP resin were obtained as follows: decoloration time of 2 h, resins dosage of 2 g, and temperature of 30 °C. Decoloration ratio, deproteinization ratio, and polysaccharide retention ratio were 62.14 ± 2.3%, 81.21 ± 2.13%, and 73.42 ± 1.96%, respectively. Furthermore, the crude TEPS was extracted and four polysaccharide fractions were isolated and purified as Tf1-a, Tf1-b, Tf2, and Tf3 by the DEAE-Sepharose FF column and the Sephasryl S100 column. In general, the antioxidant activities of the Lf1-a and Lf1-b were lower compared with Vc at the concentration of 0.1 to 3 mg/mL, but the FRAP assay, DPPH scavenging activity, and hydroxyl radical scavenging activity analysis still revealed that Tf1-a and Tf1-b possess significant antioxidant activities in vitro. At the concentration of 3 mg/mL, the reducing power of Lf1-a and Lf1-b reached 0.86 and 0.70, the maximum DPPH radical were 54.23 ± 1.68% and 61.62 ± 2.73%, and the maximum hydroxyl radicals scavenging rates were 58.76 ± 2.58% and 45.81 ± 1.79%, respectively. Moreover, there were significant correlations (r > 0.8) among the selected concentrations and antioxidant activities of TEPS major fractions Tf1-a and Tf1-b. Therefore, it is expected that Tf1-a and Tf1-b polysaccharide fractions from fermented TEPS may serve as active ingredients in functional foods.

Preparation of starch-acrylic acid-carboxymethyl cellulose copolymer and its flocculation performance towards methylene blue

Flocculants synthesized from biopolymers show the virtues of low cost, excellent efficiency and environmental friendliness. In this study, starch-acrylic acid-carboxymethyl cellulose (SAC) tertiary anionic copolymers were prepared by graft copolymerization. The optimal synthesis process was determined as raw material ratio of 1:3:1, acrylic acid neutralization degree of 70%, initiator dosage of 1.0 wt%, reaction temperature of 75 °C and reaction time of 5 h according to the flocculation performance towards methylene blue simulated waste water. Results demonstrated that the decolorization ratio of methylene blue (100 mg/L) could be up to 81.3% at the SAC dosage of 350 mg/L. The SAC achieved rapid flocculation kinetics and excellent color removal over a broad range of pH, ambient temperature and ionic strength. Furthermore, the operation cost of SAC is only one-fourth of industrial anionic polyacrylamide. The prepared SAC flocculant is promising for industrial dye wastewater treatment owing to its green raw materials, high efficiency and low operation cost.

Micro-engineering based Structuring and Valorization of Lipid Foods

Microengineering-based structuring and valorization of lipid foods were investigated. First, to control the fatty acid composition of triglycerides, modified lipases were prepared using emulsifiers and fatty acids, and applied to interesterification of fats and oils. Stearic acid was suitable for lipase activation, showing high interesterification activity. The structure of stearic acid-modified lipase was first analyzed by small-angle X-ray scattering. Next, the membrane separation performance for crude oil was investigated using hydrophobic non-porous membranes. Degumming and decolorization tests for crude soybean oil were conducted, revealing that the rejection of phospholipids and the decolorization ratio were more than 95%, representing higher quality compared to conventional methods. Membrane application to used edible oil also showed better performance than the conventional adsorption method. For practical use, improvement of the permeate flux is needed. Finally, a technology was developed for preparing monodisperse emulsions using fabricated microchannels (MCs). Efficient emulsification was achieved using asymmetrically structured MCs. The slit structure caused large distortion of the oil-water interface, and the interfacial tension induced spontaneous droplet formation. Laboratory-scale MC emulsification equipment was industrialized and used for various applications.

Preparation of Halloysite/Cerium catalytic material and study on its removal performance of cyclohexane carboxylic acid

Halloysite is a kind of clay mineral material with a unique tubular structure. In this work, halloysite/cerium catalytic materials (Ce/HNT-g-PAA) was prepared by ultraviolet light grafting and ion exchange technology. Ce/HNT-g-PAA was used to remove cyclohexane carboxylic acid (CCA) pollutants from wastewater. SEM, TEM, XRF, XRD, FT-IR and XPS detection methods were applied to characterize the structure of samples. The Ce/HNT-g-PAA showed excellent CCA degradation performance that decolorization ratio was nearly 99.5% after 120 min. The results suggested that halloysite provided stability, meanwhile, Ce3+ and hydroxyl radical played important roles during the CCA degradation process.

Gentiana straminea Maxim. polysaccharide decolored via high-throughput graphene-based column and its anti-inflammatory activity

Gentiana straminea Maxim. exhibits various biological activities. However, the purification and functions of polysaccharides in Gentiana straminea Maxim. have never been reported. Herein, by proposing a flexible 3D graphene-based decoloration column (3DD column), Gentiana straminea Maxim. polysaccharide (GMP) was high-throughput obtained and its anti-inflammatory activity was investigated. Benefiting from the large macroporous network of 3D NH2-graphene oxide hydrogel with selective adsorption towards pigments, the 3DD column exhibits high decoloration ratio (96.41%). In addition, the 3DD column provides superior practical functionality as compared to the traditional approaches, which are time-consuming and need toxic solvents, and exhibiting widespread-application for the purification of polysaccharide from other common plant species. More importantly, the decolored GMP as a natural product has promising anti-inflammatory activity on RAW264.7 cells without negative impact on cell viability. Overall, this work reveals a new functional polysaccharides and provides a flexible approach for polysaccharide decoloration, exhibiting a promising prospect for natural polysaccharides in practical application of pharmaceutical.

Green fabrication of porous microspheres containing cellulose nanocrystal/MnO2 nanohybrid for efficient dye removal

Microspheres based on cellulose nanocrystal (CNC)/metal oxide hybrid materials have great application prospects in wastewater treatment due to simultaneously adsorption, degradation ability, easily separation and recycling properties. However, the relatively small porosity and specific surface area of the CNC-based microspheres limit their adsorption ability. Herein, we reported a facile strategy to prepare porous microsphere based on CNC/MnO2 by freeze-drying the air-bubble templated emulsion, in which the sodium alginate (SA) was used as the crosslinked matrix. Thus-obtained CNC/MnO2/SA microspheres showed low density of 0.027 g/cm3 and high porosity of 98.23%. Benefiting from the high porosity, synergetic effect of CNC electrostatic adsorption and oxidative degradation ability of MnO2, the decolorization ratio of methylene blue (800 mg/mL) could be up to 95.4% in 10 min, and the equilibrium decolorization could reach 114.5 mg/g. This study provides a green and facile strategy to design porous CNC-based material for dye wastewater treatment.

Optimization of Agar Preparation Based on Transparency

To meet the requirement for high transparency of agar gel used in tissue culture, bacteriological applications, and high-quality cosmetics and food, this study on improving the transparency of agar products was carried out by using activated carbon for decolorization and perlite for aiding filtration. The results showed that the pre-coating filtration method was better than that of the mixed slurry filtration, so an orthogonal experiment optimization was conducted using the pre-coating filtration method based on the single factor experimental results. The experimental results showed that the optimal process conditions based on the transparency index were: concentration of agar of 1.30%, activated carbon dosage of 0.80%, processing temperature of 95 °C, and treatment time of 20 min. Agar products with gel transparency of 58.93% and blue-ray whiteness value of 93.82 could be obtained under these experimental conditions. The order of the factors influencing the decolorization ratio of agar was as follows: activated carbon dosage > concentration of agar > processing temperature > treatment time. The experimental results provided effective procession methods for the production enterprises based on transparency and increased economic benefits, and it was of practical significance.

Facile Preparation of Granular Copper Films as Cathode for Enhanced Electrochemical Degradation of Methyl Orange.

In this paper, granular copper films (GCFs) were prepared through electrodeposition in CuSO4 solution containing triethanolamine, and the films were used as electro-Fenton-like cathodes for degradation of methyl orange (MO). The effects of triethanolamine concentration, pH value, current intensity and temperature on the morphology of the films, as well as the MO decolorization ratio (DR), were investigated in detail. Results show that when the concentration of triethanolamine is 0.2 wt%, the prepared GCF exhibits the best performance. Under room temperature and neutral conditions, no external O2 or catalyst, MO is completely decolorized after 240 min. Compared with the commonly used carbon cathode, the GCF cathode can increase the MO decolorization rate by approximately 70.9%. The kinetics of the electrochemical degradation reaction is also discussed.

Purification and Characterization of Resistant Dextrin.

In this study, an efficient method for the purification of resistant dextrin (RD) using membrane filtration and anion exchange resin decolorization was developed, then the purified RD was characterized. In the membrane filtration stage, suspended solids in RD were completely removed, and the resulting product had a negligible turbidity of 2.70 ± 0.18 NTU. Furthermore, approximately half of the pigments were removed. Static decolorization experiments revealed that the D285 anion exchange resin exhibited the best decolorization ratio (D%), 84.5 ± 2.03%, and recovery ratio (R%), 82.8 ± 1.41%, among all the tested resins. Under optimal dynamic decolorization conditions, the D% and R% of RD were 86.26 ± 0.63% and 85.23 ± 0.42%, respectively. The decolorization efficiency of the D285 resin was superior to those of activated carbon and H2O2. Moreover, the chemical characteristics and molecular weight of RD did not change significantly after purification. The nuclear magnetic resonance spectroscopy of RD showed the formation of new glycosidic linkages that are resistant to digestive enzymes. The superior water solubility (99.14%), thermal stability (up to 200 °C), and rheological properties of RD make it possible to be widely used in food industry.

Study on Green Decolorization Technology of Agar in the Extraction Process

To establish a green decolorization technology of agar in the extraction process, the effects of activated carbon amount, decolorization time and decolorization temperature on the decolorization of agar solution extracted from Gracilaria rubra were investigated through single-factor tests with the decolorization ratio as an index. On the basis of single-factor tests, the decolorization process was optimized using orthogonal experiments. The results showed that the optimum conditions for decolorization with activated carbon were as follows: amount of activated carbon 0.6 g/100mL, decolorization time 5 min and decolorization temperature 70 °C. When the optimum conditions of decolorization with activated carbon were used on the basis of pre-treatment of diatomite, the decolorization rate of agar solution reached 81.6%, and the agar solution was nearly colourless, clear and transparent. The diatomite-pretreated decolorization of activated carbon overcame the disadvantages that chemicals are needed to acidify and bleach Gracilaria in the traditional agar extraction process. It not only avoided the use of chemicals, but also effectively decreased the water consumption and the amount of produced chemical-containing waste water.

A sustainable and nondestructive method to high-throughput decolor Lycium barbarum L. polysaccharides by graphene-based nano-decoloration

Lycium barbarum L. polysaccharides (LBPs) with outstanding biological activities are of increasing interest. Traditional purification approaches are time-consuming and often involve toxic solvents that destroy the functionality and structure of polysaccharides. Herein, we report a sustainable and nondestructive strategy for purifying LBPs using graphene-based nano-decoloration. The amination of graphene oxide (GO) enables the resulted aminated reduced GO (NH2-rGO) with abundant sp2-hybridized carbon domains, displaying high adsorption capacity toward pigments in crude polysaccharides. As such, within 5 min, NH2-rGO can highly effectively and fast to decolor LBPs, with a high decoloration ratio of 98.72% and a high polysaccharides retention ratio of 95.62%. Importantly, compared with traditional decoloration methods, NH2-rGO is nondestructive toward LBPs and has good reusability. Moreover, it exhibited widespread-use decoloration performance to decolor several common plant species. Overall, our proposed nano-decoloration approach is a general-purpose, sustainable, and nondestructive method to purify LBPs.

A dramatically improved degradation efficiency of azo dyes by zero valent iron powders decorated with in-situ grown nanoscale Fe2B

Abstract Zero valent iron (ZVI) is widely used in azo dye degradation due to the low cost and no secondary pollution. However, its low efficiency limits its wide application. In this paper, nanometer Fe2B particles with more negative open circuit potential and reductivity than Fe were in-situ decorated on the surface of low-cost construction-grade granular iron powders through sintering and improved degradation efficiency was obtained. Fe–Fe2B powders with 17 at% boron content can obtain 29 times decolorization ratio higher than unmodified Fe. The degradation efficiency continuously increases with Fe2B amount until a compact Fe2B coating formed and isolated inner Fe from the pollutant. Fe2B and Fe form galvanic cells to promote the electron transfer and reduction reaction. The compact Fe2B coating can be destroyed during the degradation process and the catalysts with compact Fe2B coating can also obtain a similar final decolorization ratio as other samples in spite of their low initial decolorization ratio. It is the amount, not the morphology of Fe2B plays the key role for the final decolorization reaction. A good catalytic activity when applied as Fenton reagent was also confirmed and a decolorization ratio of about 90% in 30 min was obtained for these new designed catalysts.

Effective promoting piezocatalytic property of zinc oxide for degradation of organic pollutants and insight into piezocatalytic mechanism

The piezoelectric zinc oxides with different morphology (ZnO nanoparticles and nanorods, hereafter abbreviated as ZnO NPs and NRs) are successfully synthesized using facile, green and harmless solid-state chemistry method at room temperature. The piezocatalytic activity of zinc oxide towards methylene blue (MB) of organic pollutants degradation has been explored under ultrasonic vibration. The ZnO NRs exhibit effectively enhanced piezocatalytic performance towards degradation dye compared with the ZnO NPs. In particular, the piezocatalytic decolorization ratio of MB solution is up to ~38% in ZnO NRs under 120 min, ~ 99% under 5.5 h and show good recycling utilization characteristics, indicating great potential for dye wastewater decolorization treatment. The main oxidizing hydroxyl radical (OH) and superoxide radicals (O2−) of the piezocatalytic reactions are confirmed and the production of piezocatalytic degradation process induced polarization electric charges. Moreover, we investigate the relationship between morphology and piezoelectric potential based on the finite element method for ZnO NPs and NRs, which further clarify the enhanced piezocatalytic activity and insight into piezocatalytic mechanism. This work offers a novel strategy towards wastewater decontamination applications and further understanding the relationship between piezocatalysis, morphology, and piezocatalytic mechanism in piezoelectric materials.

COMPARSION BETWEEN PPO FROM PLANT SOURCES AND DIFFER-ENT CHEMICALS IN TATTOO DYES DECOLORIZATION

This study was aimed to measure the decolorization of tattoo dyes by different chemicals and polyphenol oxidases from several plant sources. The tattoo inks removal market has burgeoned over the years, due to increased spread of tattooed persons about the world. Laser and surgery are presently the gold standards for removing of the tattoo. However, both of them have blemishes. Consequently, lots of persons were preferring easier, faster and cheaper procedures for tattoo remove. In this study polyphenol oxidases enzyme from many plant sources and different chemicals were used for decolorization of tattoo dyes in vitro. The polyphenol oxidase enzyme was used for removing of tattoo dyes (brown and blue) in order to demonstrate their potential in the treatment and decolorization of the tattoo, which is hazardous when removing by laser. The results show that 89 and 82 % of the brown and blue tattoo dyes respectively, were removed after 24 hours by enzyme extracted from Malva parviflora leaves, whereas the decolorization efficiency of polyphenol oxidase from other plant sources given less than 16% of the same dyes. The results for tattoo dyes decolorization by different chemicals revealed that Bimethylbenzylamine was the best chemical used with decolorization ratio 36 and 38 % for brown and blue tattoo dye, respectively.

Microwave assisted copolymerization of sodium alginate and dimethyl diallyl ammonium chloride as flocculant for dye removal

Flocculant made from natural polymers has the advantages of abundant source, affordable cost and environmental friendliness. In this work, a binary flocculant (sodium alginate-dimethyl diallyl ammonium chloride, SAD) was successfully prepared using microwave assisted free radical copolymerization technique. Based on the flocculation properties of yellow 7GL dye, the synthetic process was optimized with the amount of initiator was 0.8 wt% (equal molar ratio of ammonium peroxydisulfate and sodium bisulfite as complex initiator), sodium alginate: dimethyl diallyl ammonium chloride = 1:1 (molar ratio), and the microwave irradiation time was 18 min at the power of 280 W. The experimental results show that the color removal ratio was 73.5% at the SAD dosage of 425 mg/L for the 100 mg/L yellow 7GL simulated wastewater. The SAD also maintained excellent decolorization ratios under a wide range of flocculant dosage and environmental pH. The flocculation mechanism might be the combination of charge neutralization and bridging effect. The prepared SAD flocculant has the virtues of simple synthesis process, ecofriendliness and high decolorization ratio, which make it broad application prospect in the treatment of dye wastewater.