Removal of organic contamination from wastewater using granular activated carbon modified-Polyethylene glycol: Characterization, kinetics and isotherm study.

To effectively remove Diazinon (DZ), Amoxicillin (AMX), and Crystal Violet (CV) from aquatic environments, a novel granular activated carbon (GAC) modified with Polyethylene glycol 600 (PEG) was created and manufactured. The chemical properties were investigated using a variety of characteristic analyses, including FT-IR, XRD, FESEM, and N2 adsorption/desorption. The effectiveness of GAC-PEG's adsorption for the removal of DZ, AMX, and CV was assessed under a variety of conditions, including a pH of 4-9 for the solution, 0.003-0.05 g doses of adsorbent, 50-400 ppm starting concentration, and a reaction time of 5-25 min. For DZ, AMX, and CV adsorption, the maximum adsorption capacity (Qmax) was 1163.933, 1163.100, and 1150.300 mg g-1, respectively. The Langmuir isotherm described all of the data from these adsorption experiments, and the pseudo-second-order well explains all-adsorption kinetics. Most contacts between molecules, electrostatic interactions, π-π interactions, hydrogen bonding, and entrapment in the modified CAG network were used to carry out the DZ, AMX, and CV adsorption on the GAC-PEG. The retrievability of the prepared adsorbent was successfully investigated in studies up to two cycles without loss of adsorption efficiency, and it was shown that it can be efficiently separated.

Appraisal of Chitosan-Gum Arabic-Coated Bipolymeric Nanocarriers for Efficient Dye Removal and Eradication of the Plant Pathogen Botrytis cinerea.

The treatment of textile wastewater comprising many dyes as contaminants endures an essential task for environmental remediation. In addition, combating antifungal multidrug resistance (MDR) is an intimidating task, specifically owing to the limited options of alternative drugs with multitarget drug mechanisms. Incorporating natural polymeric biomaterials for drug delivery provides desirable properties for drug molecules, effectively eradicating MDR fungal growth. The current study fabricated the bipolymeric drug delivery system using chitosan-gum arabic-coated liposome 5ID nanoparticles (CS-GA-5ID-LP-NPs). This study focused on improving the solubility and sustained release profile of 5I-1H-indole (5ID). These NPs were characterized and tested mechanically as a dye adsorbent as well as their antifungal potencies against the plant pathogen, Botrytis cinerea. CS-GA-5ID-LP-NPs showed 71.23% congo red dye removal compared to crystal violet and phenol red from water and effectively had an antifungal effect on B. cinerea at 25 µg/mL MIC concentrations. The mechanism of the inhibition of B. cinerea via CS-GA-5ID-LP-NPs was attributed to stabilized microtubule polymerization in silico and in vitro. This study opens a new avenue for designing polymeric NPs as adsorbents and antifungal agents for environmental and agriculture remediation.

Chitin-psyllium based aerogel for the efficient removal of crystal violet from aqueous solutions.

A new alternative aerogel was prepared from low-cost chitin and psyllium biopolymers to adsorb crystal violet (CV) dye from liquid media and possibly treat effluents containing other dyes. The aerogel was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), which demonstrated that aerogel has a typical structure of amorphous materials and presented a randomly interconnected porous structure that resembles an open pore network. 2.5 g L-1 of aerogel was able to remove 86.00% of CV from solutions, and the natural pH of the CV solution was considered the more adequate for adsorption. The pseudo-second-order (PSO) model satisfactorily described the adsorption kinetics, and the Freundlich model was suitable to represent the adsorption equilibrium. The maximum experimental capacity achieved was 227.11 mg g-1, which indicates that aerogel is very efficient and competitive with several adsorbents. Tests using a simulated effluent showed that aerogel has excellent potential to treat real colored effluents.

Preparation of magnetic mesoporous metal-phenolic coordination spheres for extraction of crystal violet and leuco-metabolites in fish.

To address the undesirably low porosity of phenolic resin, a new material termed magnetic mesoporous metal-phenolic coordination spheres (Fe3O4@Co-TA) was synthesized by chelating tannic acid (TA) with metal ions. Fe3O4@Co-TA was characterized by transmission electron microscopy, scanning electron microscopy, hysteresis loop (B-H) analysis, Fourier-transform infrared spectroscopy, and N2 adsorption-desorption. The results indicated that the new material comprises mesopores (2 nm and 3 nm) and exhibits a good magnetic response (44 emu/g). Combined with high-performance liquid chromatography (HPLC), a novel method for the detection of crystal violet (CV) and leucocrystal violet (LCV) by magnetic solid-phase extraction was established. Under the optimal extraction conditions, the linear ranges of CV and LCV detection were 0.2‒60 µg/L and 0.04‒40 µg/L, the detection limits were 0.04 µg/L and 0.008 µg/L, and the enrichment factors were 435 and 460, respectively. Fe3O4@Co-TA was reused ten times without significant reduction of the extraction ability. This method was successfully used for the detection of CV and LCV in fish samples, providing an effective technique for food safety monitoring and quality control.

Modification and characterization of Nano cellulose crystalline from Eichhornia crassipes using citric acid: An adsorption study.

In this study, Eichhornia crassipes (EC) was exposed to Chemical modification using citric acid to enhancement adsorption capacity and form Modified Nano Cellulose Crystalline (MNCC) powders and comparison study was performed to remove two different dyes as Reactive blue 21 (RB21) and Crystal violet (CV). Characterization of MNCC was investigated by X-Ray Diffraction analysis (XRD), Fourier Transform infrared spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), Dynamic Light Scatting (DLS) and Transmission electron microscopy (TEM) as well as Scanning Electron Microscopy (SEM) and results, prove that MNCC is in Nano scale and has crystalline structure as well as ester form. Examine parameters such as adsorbent dose (0.1-1.00 g/40 mL), initial pH (1-10), contact time (5-120 min) and initial concentration dyes (5-10 ppm). Among the three isotherm models (Langmuir, Freundlich, and Temkin), the equilibrium adsorption confirmed and fitted well to the Langmuir isotherm model. Kinetic study showed agreement the pseudo-second-order kinetic model and Intraparticle diffusion model.

Evaluation of the selective adsorption of silica-sand/anionized-starch composite for removal of dyes and Cupper(II) from their aqueous mixtures.

A silica-sand/anionized-starch composite (CMS-SS) was prepared simply. CMS-SS was used as an efficient adsorbent for removal of cationic dyes [methyl blue (MB) and crystal violet (CV)] and metal ions [cupper(II), Cu(II)] from water in respective single and binary systems. Compared with the anionized-starch without silica sand, CMS-SS shows evidently improved adsorption capacities, i.e. approximately 653.31 ± 27.30, 1246.40 ± 34.10, and 383.08 ± 13.50 mg·g-1, for MB, CV, and Cu(II), respectively, ascribed to the additional carboxyl groups. The isotherms and kinetics study indicated that the Langmuir model and the pseudo-second-order model were more suitable. The adsorption process is thus a homogeneous monolayer chemisorption. The adsorptions of these three pollutants are spontaneous and exothermal processes driven by increasing entropy. The adsorption behaviors of CMS-SS have high pH dependence, and electrostatic attraction play an important role in adsorption. Dyes showed higher affinity to CMS-SS than metal ions causing a preferential adsorption of dye over Cu(II) in their aqueous mixture. This adsorbent after saturated adsorption could be rapidly separated from water due to its enlarged density after embedded silica sand; moreover, those rapidly recovered adsorbents were tried to use as new adsorbents for removal of an anionic dye from water due to the complete changes in their surface structures after saturated adsorption.

Alginate-whey an effective and green adsorbent for crystal violet removal: Kinetic, thermodynamic and mechanism studies.

In this study, a novel biocomposite beads is developed by gelling sodium alginate (ALG) solutions in acid whey (Aw). The formation of alginate-whey biocomposite (ALG-Aw) was confirmed by FTIR analysis where the corresponding spectrum showed the presence of characteristic absorption bands of both ALG and Aw. SEM analysis showed the presence of lactic bacteria immobilized in the alginate matrix leading to the formation of new porous structure. The adsorption properties of adsorbents were evaluated in crystal violet dye (CV) removal from aqueous solutions using a batch adsorption technique. The results showed that the maximum adsorption occurred at pH 6 and for an adsorbent dose of 0.4 g/L. The kinetic of CV removal onto ALG-Aw adsorbent can be described well by the pseudo-second order equation. The equilibrium adsorption data of ALG-Aw followed well the Redlich-Peterson isotherm which is coherent with the calculated R2, χ2 and ARE values. Calculated thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) shown that adsorption reaction is spontaneous and it is favored at low temperatures. Interactions of CV dye molecules with ALG-Aw composite beads were examined by FTIR and UV-visible DR spectroscopy.

Crystal violet dye removal using crosslinked grafted xanthan gum.

As water is the most important source for survival for all individuals around the world, water pollution via synthetic toxic dyes and microorganisms is considered as a serious worldwide environmental problem. The present work aimed to synthesize crosslinked grafted xanthan gum (XG) films with poly (N-vinyl imidazole), PVI, for both removing crystal violet (CV) dye and inhibiting Escherichia coli (E. coli) growth. XG-grafted-PVI was prepared using potassium persulfate as an initiator to give different percentage of graft yield and using N, N'-methylene bisacrylamide (MBA) as a crosslinking agent. The structure of grafted XG films was elucidated via various analysis tools including FTIR, XRD, FE-SEM and EDX. Results of CV adsorption studies showed that maximum CV removal was 99.7% (625 mgg-1) which was achieved at: 95% GY, 2.5% MBA, 40 mg of adsorbent into 50 mL of 500 mgL-1 CV dye solution, pH 7, temperature (30 °C) and adsorption time (7 h). Also, results fitted well with Langmuir isotherm model. Moreover, pseudo-first order and intraparticle diffusion model participated in the mechanism of CV adsorption on grafted XG surface, in addition to its efficient recycling ability. Furthermore, antibacterial activities results of crosslinked grafted XG revealed their high inhibiting effect for E.coli growth.

Analysis of Triphenylmethane Dye Residues and their Leuco-Forms in Frozen Fish by LC-MS/MS, Fish Microbial Quality, and Effect of Immersion in Whole Milk on Dye Removal.

A rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was validated and used to quantify crystal violet (CV), leucocrystal violet (LCV), malachite green (MG), leucomalachite green (LMG), and brilliant green (BG) residues in frozen fish (121 samples) from various countries, in order to detect the use of prohibited antibiotic dyes in fish for human consumption. The microbial quality of the fish was also assessed along with the effectiveness of a simple treatment with whole fat milk to reduce the levels of CV and LCV contamination. CV and LCV were the only two residues detected. They were found in farmed Pangasius (0.362 to 41.34 µg/kg and 0.178 to 10.58 µg/kg, respectively) and Tilapia (1.24 to 9.48 µg/kg and 1.29 to 2.81 µg/kg). Based on aerobic plate count (APC), 74%, 59%, and 55% of the samples of Tilapia fillets (from China) and Pangasius fillets (United Arab Emirates and Vietnam), and 100% and 50% of the skin samples of Hake (Argentina and U.S.A.) were of unacceptable microbial quality (APC > 107 cfu/g). Human pathogens, namely Escherichia coli, Staphylococcus aureus, and Vibrio spp., were detected in most fish. A significant reduction in CV and LCV concentrations by more than a third was achieved after immersing Pangasius and Tilapia fillets in whole fat milk for 120 minutes. These findings support the necessity of regular inspections and monitoring of CV and other antibiotic dye residues in fish, along with routine assessments of fish microbial quality, in order to protect public health. PRACTICAL APPLICATION: The described LC-MS/MS method can be used to rapidly and simultaneously quantify antibiotic dye residues in frozen fish. CV and LCV were detected in farmed Pangasius and Tilapia fillets and their concentrations was reduced by more than one third after immersing the fillets in whole milk for 120 min, a treatment which is not intended to replace safe fish farming practices upstream to artificially lower the level of banned dyes in fish. The findings support the necessity of regular inspections and monitoring of CV and other antibiotic dye residues in fish, along with assessments of fish microbial quality, to protect public health.

Mechanistic understanding of crystal violet dye sorption by woody biochar: implications for wastewater treatment.

Dye-based industries, particularly small and medium scale, discharge their effluents into waterways without treatment due to cost considerations. We investigated the use of biochars produced from the woody tree Gliricidia sepium at 300 °C (GBC300) and 500 °C (GBC500) in the laboratory and at 700 °C from a dendro bioenergy industry (GBC700), to evaluate their potential for sorption of crystal violet (CV) dye. Experiments were conducted to assess the effect of pH reaction time and CV loading on the adsorption process. The equilibrium adsorption capacity was higher with GBC700 (7.9 mg g-1) than GBC500 (4.9 mg g-1) and GBC300 (4.4 mg g-1), at pH 8. The CV sorption process was dependent on the pH, surface area and pore volume of biochar (GBC). Both Freundlich and Hill isotherm models fitted best to the equilibrium isotherm data suggesting cooperative interactions via physisorption and chemisorption mechanisms for CV sorption. The highest Hill sorption capacity of 125.5 mg g-1 was given by GBC700 at pH 8. Kinetic data followed the pseudo-second-order model, suggesting that the sorption process is more inclined toward the chemisorption mechanism. Pore diffusion, π-π electron donor-acceptor interaction and H-bonding were postulated to be involved in physisorption, whereas electrostatic interactions of protonated amine group of CV and negatively charged GBC surface led to a chemisorption type of adsorption. Overall, GBC produced as a by-product of the dendro industry could be a promising remedy for CV removal from an aqueous environment.

Basic red 2 and methyl violet adsorption by date pits: adsorbent characterization, optimization by RSM and CCD, equilibrium and kinetic studies.

The potential of raw date pits as a natural, widely available and low-cost agricultural waste has been studied in order to adsorb cationic dyes from an aqueous solution. Date pits were characterized by FTIR, SEM, BET, and XRD analysis. To optimize removal of two industrial dyes, basic red 2 (BR2) and methyl violet (MV), from aqueous solution using date pits, response surface methodology (RSM) is employed. Tests were carried out as per central composite design (CCD) with four input parameters namely contact time, temperature, initial concentration of adsorbate, and pH. Second-order polynomial model better fits experimental data for BR2 and MV and optimum values were then determined. In the optimum conditions, kinetic study was conducted and the pseudo-second-order model was found the best fitted model compared to pseudo-first-order model. Moreover, it was shown that intraparticle diffusion was not the sole controlling step and could be associated with other transfer resistance. On other hand, equilibrium isotherms were obtained for BR2 and MV and their maximum adsorption capacities were 92 and 136 mg g-1 respectively. Two-parameter isotherm models like Langmuir, Temkin, Freundlich, Dubinin-Radushkevich, and Halsay were investigated to fit equilibrium data. Three error functions of residual root mean square error, chi-square statistic, and average relative error were used to comfort us in the selected models, which were actually Dubinin-Radushkevich and Langmuir for BR2 and Frendlich, Temkin, and Halsay for MV.

Decolorization of crystal violet from aqueous solutions by a novel adsorbent chitosan/nanodiopside using response surface methodology and artificial neural network-genetic algorithm.

A novel adsorbent of chitosan/nanodiopside nanocomposite (CS-NDIO) was synthesized as a green composite for the removal of crystal violet (CV) and characterized by techniques like XRD, FT-IR, BET, and FESEM analysis. The influence of parameters like molar ratios of CS to NDIO, initial pH of the solution, dosage of adsorbent, initial concentration of CV and contact time was investigated and evaluated by central composite design (CCD; 5 levels and 4 factors). Also, Hybrid model of (ANN) model with genetic algorithm (GA) optimization was applied to the experimental data get through CCD. The optimized molar ratio of CS-NDIO was found: 20/80. Optimal parameter choice for maximum CV adsorption process using CCD and ANN-GA were as follows: pH = 7.50 and 7.499, adsorbent mass: 0.0077 and 0.0077 g, CV concentration: 20.000 and 20.002 mg/L, and contact time: 25.00 and 25.00 min, respectively. The evaluation adsorption equilibrium and kinetic data were fitted with the Langmuir monolayer isotherm model (qmax: 104.66 mg g-1 and R2: 0.9937) and pseudo-second order kinetics mechanism (R2: 0.9978). Thermodynamic parameters (R2: 0.9180, ΔH°: -74.93 kJ mol-1, ΔG°: -12.89 kJ mol-1, and ΔS°: 0.93 kJ mol-1 K-1) were calculated and indicating adsorption to be an exothermic and spontaneous process.

Urtica dioica leaves-calcium alginate as a natural, low cost and very effective bioadsorbent beads in elimination of dyes from aqueous medium: Equilibrium isotherms and thermodynamic studies.

A very effective and low cost bioadsorbents derived from Urtica dioica leaf powder (UDL) and composite beads UDL encapsulated with calcium alginate (UDL/A) were used in removal of cationic dye crystal violet (CV) from aqueous medium. The new adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR) and isoelectric points (pHpzc). Adsorption was studied in batch system according to initial CV concentration (30-150 mg/L), contact time, pH (2-11), temperature (10 to 40 °C) and adsorbent mass (10 to 200 mg). UDL and UDL/A beads showed maximum CV adsorption of 137.8 and 121.8 mg/g for 150 mg/L initial CV dye concentration, pH 6.5, 1 g/L adsorbent dose, temperature of 23 ±â€¯1 °C and contact time of 6 h. Analysis of kinetics data shows that adsorption of CV onto adsorbents was well described by pseudo-second order model. The equilibrium adsorption data fitted the Langmuir isotherm well with a maximum adsorption capacity of 1790 and 1107 mg/g respectively for UDL and UDL/A beads. Results of thermodynamic studies showed negative values of ΔG°; positive values of ΔH° 10.30 and 6.54 kJ/mol for CV onto UDL and UDL/A beads respectively. Adsorption processes are spontaneous, physical and endothermic in nature.

Synthesis of Co3O4/graphene nanocomposite using paraffin wax for adsorption of methyl violet in water.

This study discusses the use of Co3O4 impregnated graphene (CoOIG) as an efficient adsorbent for the removal of methyl violet (MV) dye from wastewater. CoOIG nanocomposites have been prepared by pyrolyzing paraffin wax with cobalt acetate. The synthesised nanocomposite was characterised by X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Fourier transform infrared spectroscope, Raman spectroscopy, and Brunauer-Emmett-Teller isotherm studies. The above studies indicate that the composites have cobalt oxide nanoparticles of size 51-58 nm embedded in the graphene nanoparticles. The adsorption studies were conducted with various parameters, pH, temperature and initial dye concentration, adsorbent dosage and contact time by the batch method. The adsorption of MV dye by the adsorbent CoOIG was about 90% initially at 15 min and 98% dye removal at pH 5. The data were fitted in Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich and Sips isotherm models. Various thermodynamic parameters like Gibbs free energy, enthalpy, and entropy of the on-going adsorption process have also been calculated.

Sono-assisted adsorption of Cristal Violet dye onto Tunisian Smectite Clay: Characterization, kinetics and adsorption isotherms.

The present work describes the removal of Crystal violet from aqueous solution by Sono-assisted adsorption on Raw Tunisian Smectite Clay (RSC). This material was purified by dispersion in water and extraction of the fraction with a particle size smaller than 2 µm. the resulting material was characterized by XRD, TEM, BET, surface area and pore volume measurements. Batch studies were carried out to investigate the effect of experimental factors such as contact time (0-60 min), pH (2.5-11), adsorbent dose (0.05-0.3 g/L), and initial dye concentration (12.5-100 mg/L) on the Sono-assisted adsorption of Crystal violet dye. Adsorption kinetics was well fitted by pseudo-second order kinetic model. Langmuir (R2 = 0.988), Freundlich (R2 = 0.968), Langmuir-Freundlich (R2 = 0.997) and Toth (R2 = 0.999) isotherms were fitted to describe the equilibrium of Crystal violet Sono-assisted adsorption process. The results suggested that Natural Tunisian Smectite Clay is suitable as a sorbent material for Sono-assisted adsorption of Crystal violet dye from aqueous solutions.

Efficient removal of crystal violet from aqueous solutions with Centaurea stem as a novel biodegradable bioadsorbent using response surface methodology and simulated annealing: Kinetic, isotherm and thermodynamic studies.

The novel green bioadsorbent, Centaurea stem, was utilized for crystal violet removal from aqueous solutions. SEM and FT-IR were used for characterization of Centaurea stem. The effects of the pH, time, temperature, bioadsorbent amount, and initial dye concentration were investigated. Response surface methodology was used to depict the experimental design and the optimized data of pH 12.57, time 19.661, temperature 38.94 °C, amount of bioadsorbent 12.218 mg, and initial dye concentration 36.62 mg L-1 were achieved. Moreover, artificial neural network (ANN) and simulated annealing (SA) were applied for prediction and optimization of the process respectively. The SA acquired optimum conditions of 10.114, 7.892 min, 25.127 °C, 64.405 mg L-1, 14.54 mg for pH, time, temperature, initial dye concentration, and bioadsorbent amount, respectively which were more close to the experimental results and indicated higher ability of SA-ANN in prediction and optimization of the process. The adsorption isotherms confirm the experimental data were appropriately fitted to the Langmuir model with high adsorption capacity of 476.190 mg g-1. The thermodynamic parameters were evaluated. The positive ΔH° and ΔS° values described endothermic nature of adsorption. The adsorption of crystal violet followed the pseudo-second order kinetic model.

Facile preparation of nitrogen and sulfur co-doped graphene-based aerogel for simultaneous removal of Cd2+ and organic dyes.

The need in simultaneous removal of heavy metals and organic compounds dictates the development of synthetic adsorbents with tailor-made properties. A nitrogen (N) and sulfur (S) co-doped graphene-based aerogel (GBA) modified with 2,5-dithiobisurea was synthesized hydrothermally for simultaneous adsorption of Cd2+ and organic dyes-safranin-O (SO), crystal violet (CV), and methylene blue (MB). 2,5-Dithiobisurea was used as nitrogen and sulfur sources to introduce N and S-containing functional group onto graphene oxide. The adsorption mechanism of GBA towards Cd2+ and organic dyes was studied by Dumwald-Wagner models and the results showed that surface and intraparticle diffusion was the key factor in controlling the rate of adsorption. The maximum adsorption capacities of GBA towards Cd2+, SO, CV, and MB comprised 1.755, 0.949, 0.538, and 0.389 mmol/g in monocomponent system, respectively. Adsorption synergism was observed with respect to Cd2+ in presence of the dyes. The performance of GBA with respect to Cd2+ removal from binary solutions, Cd2+-SO, Cd2+-CV, and Cd2+-MB, was enhanced by the presence of the dyes significantly, while the adsorption capacities towards the dyes were not affected by the presence of Cd2+.

Simultaneous determination of Brilliant Green and Crystal Violet dyes in fish and water samples with dispersive liquid-liquid micro-extraction using ionic liquid followed by zero crossing first derivative spectrophotometric analysis method.

In this study, dispersive liquid-liquid micro-extraction using ionic liquid (IL-DLLME) combined with zero crossing first derivative spectrophotometric method was applied to quantitative determination of triphenylmethane dyes in binary mixtures. The 1-methyl-3-octylimidazolium hexafluorophosphate [OMIM][PF6] ionic liquid was used to extract Brilliant Green (BG) and Crystal Violet(CV) dyes from aqueous solutions. The amplitude of the zero crossing first derivative spectra at 670 nm and 532 nm were selected for the determination of BG and CV, respectively. Significant factors influencing the extraction of BG and CV such as sample pH, kind of extraction solvent, amount of extractant, extraction and centrifuging times and ionic strength were investigated. Under the optimal conditions, the calibration curves for the simultaneous determination of both dyes were found to be linear in the range of 10-500 µg L-1 with detection limits (LODs) of 2.7 µg L-1 and 1.4 µg L-1 for BG and CV, respectively. The relative standard deviation (RSD%) for five replicate simultaneous determinations of BG and CV were 4.7% and 1.7%, respectively. Extraction efficiencies of the BG and CV dyes in the presence of interfering ions were also investigated. Sample preparation based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction combined with the IL-DLLME method and zero crossing first derivative spectrophotometric detection was applied for the simultaneous analysis of BG and CV in fish and water samples with quantitative recoveries.

Synthesis of magnetic mesoporous metal-organic framework-5 for the effective enrichment of malachite green and crystal violet in fish samples.

A novel, magnetic and mesoporous Fe3O4@PEI-MOF-5 material was synthesized for the effective enrichment of malachite green (MG) and crystal violet (CV) in fish samples. The Fe3O4@PEI-MOF-5 material was prepared by a facile two-step solvothermal approach in which Fe3O4@PEI and MOF-5 were connected through chemical bonds. Characterization of the newly synthesized Fe3O4@PEI-MOF-5 material was performed by Fourier transform infrared spectroscopy, X-ray diffractometry, vibrating sample magnetometry, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy. This new material was determined to have high magnetization and chemical stability, a large surface area and a distinctive morphology. An effective enrichment and detection method for MG and CV was subsequently developed by combining the Fe3O4@PEI-MOF-5 material with ultra-high-performance liquid chromatography-tandem mass spectrometry. The linearity ranges of this approach for MG and CV were 1-500ng/mL and 0.25-500ng/mL, respectively, with correlation coefficients (R2) of 0.999. The limits of detection (LODs) of the method for MG and CV were 0.30ng/mL and 0.08ng/mL, respectively, indicating that the Fe3O4@PEI-MOF-5 material had good adsorption properties for MG and CV. Fe3O4@PEI-MOF-5 can be expected to also provide efficient enrichment of MG and CV in other complex matrices.

Three-dimensional polylactic acid@graphene oxide/chitosan sponge bionic filter: Highly efficient adsorption of crystal violet dye.

Owing to low bearing capacity and efficiency, traditional filters or adsorbents for removal of contaminants like crystal violet (CV) dye required frequent replacement. Besides, the combination of three-dimensional (3D) printing and bionics could break the constraints of traditional configuration. In this study, a novel depth-type hybrid polylactic acid (PLA)@graphene oxide (GO)/chitosan (CS) sponge filter with bionic fish-mouth structure was prepared and fabricated, assisted by 3D printing and double freeze-drying technology, according to the theories of vertical cross-step filtration and swirling flow. And GO/CS sponge and its filtering device were characterized by FITR, SEM, water adsorption and so on. Moreover, it was explained that the impact factors on dye removal mechanism, like GO content (or CS content), contact time, pH, temperature and bionic configuration. As a result, the bionic 3D filtering device demonstrated excellent removal efficiency (97.8±0.5% for CV) and GO/CS sponge exhibited higher strength (74.5±3.5MPa) at the condition of GO content of 9wt%, contact time of 46min, pH of 8 and 35°C, respectively. Therefore, the resulting 3D PLA@GO/CS sponge bionic filter via gravity and vortex driving provided new alternatives for effectively dye-water separation, and it showed great promise for application of biological macromolecules in adsorption.