Investigation study of methyl violet photodegradation over alginate-carboxymethyl cellulose/titanium(IV) oxide/covalent organic frameworks bio-nanocomposite beads under ultraviolet irradiation.

Concerned about water treatment, it is of great importance to present new approaches for improving photocatalytic activity. Since photocatalysis is ubiquitous in almost all chemical manufacturing processes, the development of photocatalytic systems carries significance for our environment. In this regard, three different amounts of covalent organic frameworks decorated with titanium(IV) oxide nanoparticles (TiO2/COF hybrids) in Alginate-Carboxymethyl cellulose (Alg-CMC) blend matrix were prepared under ultrasound irradiation, which Citric acid and Calcium chloride acted as two green cross-linkages. Based on the physio-chemical analyses of these bio-nanocomposite (bio-NC) beads, the Alg-CMC blend polymer appeared to be the best candidate for a disparity of TiO2/COF hybrids. Not only did COF aid to increase the distribution of TiO2 nanoparticles, but it declined the bandgap energies. The resultant Alg-CMC/TiO2/COF (TiO2/COF = 15:6) bio-NC beads demonstrated efficient photodegradation activity towards Methyl violet (MV) under Ultraviolet light. The obtained results of scavenger studies indicated that superoxide radicals and electron agents played a major role in MV degradation. Further investigation confirmed that single oxygen addition and N-de-methylation could be two important pathways for the decomposition of MV by these bio-NC beads.

Photocatalytically active layered double hydroxide-PVDF composite membranes for effective remediation of dyes contaminated water.

In this work, polyvinylidene fluoride (PVDF) intercalated CuFe layered double hydroxides (LDH) membranes were fabricated and investigated for UV-LED/persulfate degradation of methylene blue (MB), crystal violet (CV), methyl orange (MO), and Eriochrome black T (EBT) dyes from water. The PVDF-CuFe membrane exhibited improved heterogeneity, surface functionality (CuO, Fe-O, Cu-O-Fe), surface roughness, and hydrophilicity. The process parameters were optimized by response surface methodology, and maximum MB removal (100%) was achieved within 45.22-178.5 min at MB concentration (29.45-101.93 mg/L), PP concentration (0.5-2.41 g/L) and catalyst dosage (1.84-1.95 g/L). The degradation kinetics was well described by a pseudo-first-order model (R2 = 0.982) and fast reaction rate (0.029-0.089/min). The MB dye degradation mechanism is associated with HO·/SO4•- reactive species generated by Fe3+/Fe2+ or Cu2+/Cu+ in PVDF-CuFe membrane and PP dissociation. The PVDF-CuFe membrane demonstrated excellent recyclability performance with a 12% reduction after five consecutive cycles. The catalytic membrane showed excellent photocatalytic degradation of crystal violet (100%), methyl orange (79%), and Eriochrome black T (60%). The results showed that UV-LED/persulfate-assisted PVDF-CuFe membranes can be used as a recyclable catalyst for the effective degradation of dye-contaminated water streams.

Capabilities of GPT-4o and Gemini 1.5 Pro in Gram stain and bacterial shape identification.

Aim: Assessing the visual accuracy of two large language models (LLMs) in microbial classification.Materials & methods: GPT-4o and Gemini 1.5 Pro were evaluated in distinguishing Gram-positive from Gram-negative bacteria and classifying them as cocci or bacilli using 80 Gram stain images from a labeled database.Results: GPT-4o achieved 100% accuracy in identifying simultaneously Gram stain and shape for Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro showed more variability for similar bacteria (45, 100 and 95%, respectively). Both LLMs failed to identify both Gram stain and bacterial shape for Neisseria gonorrhoeae. Cumulative accuracy plots indicated that GPT-4o consistently performed equally or better in every identification, except for Neisseria gonorrhoeae's shape.Conclusion: These results suggest that these LLMs in their unprimed state are not ready to be implemented in clinical practice and highlight the need for more research with larger datasets to improve LLMs' effectiveness in clinical microbiology.

This study looked at how well large language models (LLMs) could identify different types of bacteria using images, without having any specific training in this area beforehand.We tested two LLMs with image analysis capabilities, GPT-4o and Gemini 1.5 Pro. These models were asked to determine whether bacteria were Gram-positive or Gram-negative and whether they were round (cocci) or rod-shaped (bacilli). We used 80 images of four stained bacteria from a labeled database as a reference for this test.GPT-4o was more accurate in identifying both the Gram stain and shape of the bacteria compared with Gemini 1.5 Pro. GPT-4o had excellent accuracy in correctly classifying the Gram stain and bacterial shape of Clostridium perfringens, Pseudomonas aeruginosa and Staphylococcus aureus. Gemini 1.5 Pro had mixed results for these bacteria. However, both models struggled with Neisseria gonorrhoeae, failing to correctly identify its Gram stain and shape.The study shows that while these LLMs have potential, they are not ready to be implemented in clinical practice. More research and larger datasets are needed to improve their accuracy in clinical microbiology.

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.

Optimization of Extraction Conditions from Gac Fruit and Utilization of Peel-Derived Biochar for Crystal Violet Dye Removal.

Gac fruit (Momordica cochinchinensis Spreng.) is a prominent source of carotenoids, renowned for its exceptional concentration of these compounds. This study focuses on optimizing the extraction of active components from the aril of gac fruit by evaluating the effects of extraction temperature, solid-liquid ratio, and extraction time. The primary objective is to maximize the yield of gac oil while assessing its antioxidant capacity. To analyze the kinetics of the solid-liquid extraction process, both first-order and second-order kinetic models were employed, with the second-order model providing the best fit for the experimental data. In addition, the potential of gac fruit peel as a precursor for biochar production was investigated through carbonization. The resultant biochars were evaluated for their efficacy in adsorbing crystal violet (CV) dye from aqueous solutions. The adsorption efficiency of the biochars was found to be dependent on the carbonization temperature, with the highest efficiency observed for BCMC550 (91.72%), followed by BCM450 (81.35%), BCMC350 (78.35%), and BCMC250 (54.43%). The adsorption isotherm data conformed well to the Langmuir isotherm model, indicating monolayer adsorption behavior. Moreover, the adsorption kinetics were best described by the pseudo-second-order model. These findings underscore the potential of gac fruit and its byproducts for diverse industrial and environmental applications, highlighting the dual benefits of optimizing gac oil extraction and utilizing the peel for effective dye removal.

Enhancing methyl violet 2B pollutant removal from wastewater using Al-MOF encapsulated with poly (itaconic acid) grafted crosslinked chitosan composite sponge: Synthesis, characterization, DFT calculation, adsorption optimization via Box-Behnken Design.

In this research, aluminum metal-organic framework encapsulated with poly (itaconic acid) grafted crosslinked chitosan composite sponge (Al-MOF@PIC) was prepared. SEM, FTIR, XPS, XRD, and BET techniques were employed to thoroughly characterize the synthesized material and establish its structure and characteristics. The study discovered that the Al-MOF@PIC is an efficient way to remove dyes, which constitute a significant number of contaminants in industrial wastewater. Subsequently the adsorption of methyl violet 2B (MV-2B) dye, the surface area, pore size, and pore volume of the adsorbent decreased from 1860.68 m2/g, 1.62 nm, and 1.52 cc/g to 1426.45 m2/g, 1.11 nm, and 0.92 cc/g, individually. This modification suggested that a portion of the MV-2B dye had been removed by adsorption over the adsorbent's pores. The excellent adsorption capacity of the material was further confirmed by batch adsorption tests, which displayed a maximum adsorption capability of 646.76 mg/g for the elimination of MV-2B dye. The high adsorption energy of 26.8 kJ/mol designates that chemisorption is primarily responsible for MV-2B dye adsorption against the sponge adsorbent. The Al-MOF@PIC composite sponge demonstrated exceptional reusability over six cycles, demonstrating its strength and durability. The Al-MOF@PIC composite sponge successfully removes MV-2B from water by pore filling, π-π stacking, hydrogen bonding, and electrostatic interactions, which are the key mechanisms behind the adsorption of the dye pollutant. Its potential for practical applications is further demonstrated using Box Behnken-design (BBD) to optimize the adsorption consequences.

Harnessing synergy: Polydopamine-hBN integration in electrospun nanofibers for Co (II) ion, methylene blue and crystal violet dyes adsorption.

In today's world, major pollutants, such as cationic dyes and heavy metals, pose a serious threat to human health and the environment. In this study, a novel adsorbent was created through the electrospinning of polyvinyl alcohol/polyacrylic acid (PVA/PAA), incorporated with hexagonal boron nitride (hBN) coated with polydopamine (PDA). The integration of hBN and PDA substantially enhanced the adsorption capacity of the PVA/PAA fibers, making them highly effective in adsorbing cationic dyes such as methylene blue and crystal violet, as well as cobalt (II) ions, from contaminated water. The adsorbents were assessed to understand how their adsorption behavior varies with pH, as well as to examine their adsorption kinetics and isotherms. The results indicate that the PVA/PAA-hBN@PDA adsorbent has maximum adsorption capacities of 1029.57 mg/g, 793.65 mg/g, and 62.46 mg/g for methylene blue, crystal violet, and cobalt (II) ions, respectively. This underscores the superior performance of the PVA/PAA-hBN@PDA adsorbent when compared to both the PVA/PAA and PVA/PAA-hBN adsorbents. The adsorption kinetics adhered to a pseudo-second-order model, indicating chemisorption, whereas the Langmuir model implied a monolayer adsorption. Overall, the findings of this study highlight the efficacy of harnessing the synergistic capabilities of hBN and PDA within the PVA/PAA-hBN@PDA adsorbents, providing an efficient and eco-friendly approach to removing cationic dyes and heavy metals from contaminated water, and thereby contributing to a cleaner and safer environment for all.

Exploring Ficus religiosa inflorescence powder as an eco-friendly and sustainable solution for the removal of crystal violet with a disposal solution.

This study investigates the potential of using Ficus religiosa inflorescence (peepal tree) as an efficient solution for removing crystal violet from simulated and industrial wastewater. Various analyses were conducted to understand the adsorbent's structure, including particle morphology, BET surface area, FTIR, and pHZPC. The adsorption process was studied under different physicochemical factors such as temperature, concentration, contact time, and pH. Results revealed rapid adsorption, with 94.15% removal efficiency within the first 15 min at neutral pH. The highest observed adsorption capacity was 198.03 mg g-1, following pseudo-second-order kinetics (R2 = 0.99), indicating chemisorption. The Langmuir model accurately described the adsorption pathway (R2 = 0.99), showing monolayer adsorption. Thermodynamic analysis indicated an exothermic, feasible, and spontaneous process with increased entropy. The adsorbent could be easily regenerated using a 1:1 MeOH/H2O mixture for up to three cycles, yielding up to 73.86%. Real-time application with industrial effluent containing crystal violet showed up to 44.70% adsorption. The experiments demonstrated reliability with evaluated standard deviations (0.017935-0.000577) and relative standard deviations (0.439-0.673%), confirming statistical reliability. In conclusion, it presents a sustainable and eco-friendly approach for removing crystal violet dye from diverse wastewater sources.

Improved productivity and dye removal performance of Trametes versicolor pellets using rice husk as a co-substrate.

Pellet production represents a critical step for several processes requiring fungal biomass, nevertheless, its optimization is seldom reported. The use of finely ground rice husk as a microcarrier and co-substrate permitted a marked increase (≈ 2.7×) in the productivity of fungal pellet production using Trametes versicolor compared to traditional production methods. The pellets show similar structure and smaller size compared to typical sole-mycelium pellets, as well as comparable laccase activity. The efficiency of the pellets for biodegradation was confirmed by the removal of the crystal violet dye, achieving significantly faster decolorization rates compared to the traditionally produced pellets. The use of these pellets during the continuous treatment of the dye in a stirred tank bioreactor resulted in 97% decolorization operating at a hydraulic residence time of 4.5 d.

Crystal Violet Selectively Detects Aß Oligomers but Not Fibrils In Vitro and in Alzheimer's Disease Brain Tissue.

Deposition of extracellular Amyloid Beta (Aß) and intracellular tau fibrils in post-mortem brains remains the only way to conclusively confirm cases of Alzheimer's Disease (AD). Substantial evidence, though, implicates small globular oligomers instead of fibrils as relevant biomarkers of, and critical contributors to, the clinical symptoms of AD. Efforts to verify and utilize amyloid oligomers as AD biomarkers in vivo have been limited by the near-exclusive dependence on conformation-selective antibodies for oligomer detection. While antibodies have yielded critical evidence for the role of both Aß and tau oligomers in AD, they are not suitable for imaging amyloid oligomers in vivo. Therefore, it would be desirable to identify a set of oligomer-selective small molecules for subsequent development into Positron Emission Tomography (PET) probes. Using a kinetics-based screening assay, we confirm that the triarylmethane dye Crystal Violet (CV) is oligomer-selective for Aß42 oligomers (AßOs) grown under near-physiological solution conditions in vitro. In postmortem brains of an AD mouse model and human AD patients, we demonstrate that A11 antibody-positive oligomers but not Thioflavin S (ThioS)-positive fibrils colocalize with CV staining, confirming in vitro results. Therefore, our kinetic screen represents a robust approach for identifying new classes of small molecules as candidates for oligomer-selective dyes (OSDs). Such OSDs, in turn, provide promising starting points for the development of PET probes for pre-mortem imaging of oligomer deposits in humans.

Response surface and DFT protocols for improvement of the adsorption process of lignocellulosic-based biomass for the removal of basic dyes.

Jatobá-do-cerrado fruit shells, archetypical of lignocellulosic-based biomass, were used as an adsorbent to remove crystal violet (CV) and methylene blue (MB) from water. The adsorbent was characterized using various techniques, and kinetic studies showed dye adsorption followed second-order kinetics. An experimental design investigated the effects of pH and temperature on removal efficiency, with a quadratic model fitting the data best. The results suggest pH influences MB's adsorption capacity more than temperature and at 25 °C and pH 8, MB had a desirability value of 0.89, with 95 % removal efficiency. For CV, temperature had a greater influence, with a desirability value of 0.874 at 25 °C and pH 10, and 95 % removal efficiency. Adsorption isotherm studies revealed maximum adsorption capacities of 123.0 mg·g-1 and 113.0 mg·g-1 for CV and MB, respectively. Experimental thermodynamic parameters indicated an endothermic and spontaneous process which it was supported by quantum chemistry calculations. The protocols developed confirmed the potential for adsorbing CV and MB dyes in water, achieving over 73.1 and 74.4 mg g-1 dyes removal.

Effectiveness of polyacrylamide-g-gelatin/ACL/Mg-Fe LDH composite hydrogel as an eliminator of crystal violet dye.

Cationic synthetic dyes are one of the hazards in aqueous solutions that can affect the health of humans and living organisms. In the current work, polyacrylamide (PAM)-g-gelatin hydrogel and modified PAM-g-gelatin hydrogel using activated carbon of Luffa cylindrica (ACL) and ACL/Mg-Fe LDH were applied to eliminate crystal violet (CV), a cationic dye, from water media. The hydrogels were synthesized using free radical polymerization approach, and the hydrogels were characterized using FTIR, XRD, TGA-DTG, BET, SEM, and EDX-Map. The surface area of ACL, ACL/Mg-Fe LDH, PAM-g-gelatin, PAM-g-gelatin/ACL, and PAM-g-gelatin/ACL/Mg-Fe LDH were 99.71, 141.99, 0.74, 1.47, and 1.65 m2/g, respectively, which shows that the presence of ACL and ACL/Mg-Fe LDH improved the area of the hydrogels. The maximum abatement of CV using PAM-g-gelatin (92.81%), PAM-g-gelatin/ACL (95.71%), and PAM-g-gelatin/ACL/Mg-Fe LDH (98.25%) was obtained at pH = 9, temperature 25 °C, 10 mg/L CV, 60 min time, and adsorber dose of 2 g/L (for PAM-g-gelatin) and 1.5 g/L (other samples). The value of thermodynamic factors confirmed that the abatement process is exothermic and spontaneous. The kinetics data followed the pseudo-second kinetic (PSO) model. The Langmuir isotherm model had a more remarkable ability to describe the equilibrium data. The maximum adsorption capacity for PAM-g-gelatin, PAM-g-gelatin/ACL, and PAM-g-gelatin/ACL/Mg-Fe LDH was determined 35.45, 39.865, and 44.952 mg/g, respectively. Generally, the studied hydrogels can eliminate dyes from wastewater and be used as effective adsorbers.

Constructing the synergistic effects of chitosan and ionic liquid on SPEEK polymer for efficient adsorption of crystal violet dye.

In the study, a novel chitosan biopolymer and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid (IL)-incorporated sulfonated poly (ether ether ketone) (SPEEK) composite (Ch-IL@SPEEK) was prepared for adsorption of cationic crystal violet (CV) dye. The proposed composite was well characterized by several techniques. CV adsorption performance was examined via batch studies by varying various variables involving adsorbent dosage, contact time pH and temperature. The isotherm results were demonstrated the adsorption characters of the processes were Langmuirian. The maximum adsorption capacity was determined as 77.66 mg g-1 for the composite which was significantly higher than SPEEK (qmax = 45.36 mg g-1). The determined equilibrium time of the operated system was 360 min and the kinetic model was assessed as Elovich. At low pHs the protonated surface groups repelled the positively charged CV and the adsorption rate increased with increasing pH. The process is spontaneous and favorable as it proceeds via endothermic interactions. Furthermore, even at the end of 5 successful adsorption cycles, 77.86 % CV removal was obtained. Remarkable efficiencies were also achieved in the removal performance of different organic pollutants. Based on the reported results, Ch-IL@SPEEK composite were exhibited as an impressive adsorbent material for adsorption processes.

Efficient removal of crystal violet dye from water using zinc ferrite-polyaniline nanocomposites.

Nanomaterials are widely employed in wastewater treatment, among which nanoferrites and their composites hold significant prominence. This study adopts a green approach to synthesize zinc ferrite nanoparticles, subsequently integrating them with polyaniline (PANI) to fabricate the ZnFe2O4-PANI nanocomposite. Characterization of the prepared ZnFe2O4-PANI nanocomposite was conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopic (SEM) techniques. Using Scherrer's equation, the crystallite size of the synthesized zinc ferrite nanoparticles was found to be 17.67 nm. SEM micrographs of the ZnFe2O4-PANI nanocomposite revealed that in situ polymerization of ZnFe2O4 with polyaniline transforms the amorphous surface morphology of the polymer into a homogeneous nanoparticle structure. The adsorption of crystal violet (CV) dye onto the surface of the ZnFe2O4-PANI nanocomposite depends on pH, adsorbent dosage, temperature, concentration levels and duration. The Langmuir adsorption model fitted the data well, indicating adherence to a pseudo-second-order kinetic pattern. Thermodynamic values ΔG°, ΔH° and ΔS° indicated that the adsorption process occurred spontaneously. Advantages and disadvantages of the technique have also been highlighted. Mechanism of adsorption is discussed. From the obtained results, it is evident that the ZnFe2O4-PANI nanocomposite holds promise as a sorbent for the removal of dye from wastewater.

Microwave synthesized novel biomass carbon dots applied in the fluorescent detection of crystal violet.

To establish a new method for detecting crystal violet (CV), a harmful dye, herein, a genre of novel biomass carbon dots (CDs) was synthesized via a microwave method and employed as a fluorescent probe, in which water spinach and polyethylene glycol (PEG) performed as raw materials. Based on the inner filter effect (IFE) between the luminescent CDs and CV, the blue emission of this probe at 430 nm could be quenched by CV. Hence, a new strategy was proposed to selectively determine CV in aquaculture ambient. Moreover, under the optimal experiment conditions, this method showed a good linearity between the concentration of CV (c) and fluorescence quenching rate (ΔF/F0) in the concentration range of 4-200 µmol/L with the corresponding correlation coefficient (r) and the detection limit of 0.997 and 710 nmol/L, respectively. With advantages of environmental protectivity, sensitivity, affordability, and user-friendliness, the facilely fabricated CDs could be successfully applied in detecting CV in aquaculture samples, providing a technical foundation for monitoring the pollution of CV and ensuring the quality and safety of aquatic products.

Decolorization and degradation of crystal violet dye by electron beam radiation: Performance, degradation pathways, and synergetic effect with peroxymonosulfate.

Ionizing radiation (mainly including gamma ray and electron beam) technology provides a more efficient and ecological option for dye-containing wastewater treatment, which is supported by its successful achievements in industrial-scale applications. However, the degradation pathway of triphenylmethane dyes by radiation technology is still unclear. In this study, crystal violet (CV) was selected as representative cationic triphenylmethane dye, the decolorization and degradation performance by electron beam radiation technology was systematically evaluated. The results showed that CV can be efficiently decolorized and mineralized by radiation, and its degradation kinetics followed the first-order kinetic model. The effect of inorganic anions and chelating agents commonly existed in dye-containing wastewater on CV decolorization and total organic carbon (TOC) removal was explored. Quenching experiments, density functional theory (DFT) calculation and high performance liquid chromatography mass spectrometry (HPLC-MS) analysis were employed to reveal CV decolorization and degradation mechanism and pathway, which mainly included N-demethylation, triphenylmethane chromophore cleavage, ring-opening of aromatic products and further oxidation to carboxylic acid, and mineralization to CO2 and H2O. Additionally, electron beam radiation/PMS process was explored to decrease the absorbed dose required for decolorization and degradation, and the synergetic effect of radiation with PMS was elucidated. More importantly, the findings of this study would provide the support for treating actual dyeing wastewater by electron beam radiation technology.

Adsorption removal of cationic dyes from wastewater using the corn straw modified with diethylenetriaminepentacetic acid ligand.

Taking the thiazide cationic dye methylene blue (MB), triphenylmethane cationic dye crystal violet (CV), monoazo cationic dye cationic red 46 (R-46), and polycarboxycyanine cationic dye cationic rosé FG (P-FG) as the research objects, the adsorption behaviors of a self-made corn straw modified adsorbent HQ-DTPA-I for the dyes were investigated in depth. Under optimized conditions, HQ-DTPA-I can quickly adsorb most dyes within 3 min and reach equilibrium adsorption in 15-20 min. The removal rates of HQ-DTPA-I to MB, CV, R-46 and AP-FG can reach 95.28 %, 99.78 %, 99.28 % and 98.53 %, respectively. It also has good anti-interference ability for common ions present in most actual dye wastewater. For six consecutive adsorption-desorption cycles, the adsorption performance of HQ-DTPA-I can still reach 80.17 %, 81.61 %, 90.77 % and 83.48 % of the initial adsorption capacity, indicating good recovery performance. Based on Gaussian density functional theory to calculate its surface potential energy, it is found that the adsorption mechanism of HQ-DTPA-I for the cationic dyes is mainly due to the electrostatic interaction between the carboxyl groups in ligand DTPA and amino groups in dye molecules.

Removal of doxorubicin hydrochloride and crystal violet from aqueous solutions using spray-dried niobium oxide coated with chitosan-activated carbon: Experimental and DFT calculations.

Spray-dried niobium oxide coated with chitosan-activated carbon (NIC) was synthesized and used to remove doxorubicin hydrochloride and crystal violet from aqueous solutions under different parameters such as solution pH (2, 4, 6, and 8), contact time (1 to 9 h), initial concentration (20 to 200 mg L-1), and competing ions (0.1 M of CaCl2 and NaCl). The addition of 5 % chitosan-activated carbon to the matrix of niobium oxide slightly increased the specific surface area from 26 to 30 m2 g-1, with the introduction of a carboxylic functional group. This led to an increase in the amount of adsorbed doxorubicin hydrochloride (DOH) from 30 to 44 mg g-1 and that of crystal violet (CV) from 15 to 32 mg g-1 from the initial respective 100 mg L-1 at pH 8. The data from the concentration study fitted into Liu isotherm having adsorption capacity of 128 and 57 mg g-1 for DOH and CV respectively, while pseudo first and second order are more suitable for adsorption kinetics. The additional functional groups on the IR spectrum of NIC after the adsorption of DOH and CV confirmed the interaction between NIC and the adsorbates' molecules. The mechanism of adsorption was supported by DFT calculations.

Polypyrrole-decorated bentonite magnetic nanocomposite: A green approach for adsorption of anionic methyl orange and cationic crystal violet dyes from contaminated water.

In the presented study, a novel polypyrrole-decorated bentonite magnetic nanocomposite (MBnPPy) was synthesized for efficient removal of both anionic methyl orange (MO) and cationic crystal violet (CV) dyes from contaminated water. The synthesis of this novel adsorbent involved a two-step process: the magnetization of bentonite followed by its modification through in-situ chemical polymerization. The adsorbent was characterized by SEM/EDX, TEM/SAED, BET, TGA/DTA-DTG, FTIR, VSM, and XRD studies. The investigation of the adsorption properties of MBnPPy was focused on optimizing various parameters, such as dye concentration, medium pH, dosage, contact time, and temperature. The optimal conditions were established as follows: dye concentration of Co (CV/MO) at 100 mg/L, MBnPPy dosage at 2.0 g/L, equilibrium time set at 105 min for MO and 120 min for CV, medium pH adjusted to 5.0 for MO dye and 8.0 for CV dye, and a constant temperature of 303.15 K. The different kinetic and isotherm models were applied to fit the experimental results, and it was observed that the Pseudo-2nd-order kinetics and Langmuir adsorption isotherm were the best-fitted models. The maximal monolayer adsorption capacities of the adsorbent were found to be 78.74 mg/g and 98.04 mg/g (at 303.15 K) for CV and MO, respectively. The adsorption process for both dyes was exothermic and spontaneous. Furthermore, a reasonably good regeneration ability of MBnPPy (>83.45%/82.65% for CV/MO) was noted for up to 5 adsorption-desorption cycles with little degradation. The advantages of facile synthesis, cost-effectiveness, non-toxicity, strong adsorption capabilities for both anionic and cationic dyes, and easy separability with an external magnetic field make MBnPPy novel.

Food-grade algae modified Schiff base-chitosan benzaldehyde composite for cationic methyl violet 2B dye removal: RSM statistical parametric optimization.

This work aims to apply the use of food-grade algae (FGA) composited with chitosan-benzaldehyde Schiff base biopolymer (CHA-BD) as a new adsorbent (CHA-BA/FGA) for methyl violet 2B (MV 2B) dye removal from aqueous solutions. The effect of three processing variables, including CHA-BA/FGA dosage (0.02-0.1 g/100 mL), pH solution (4-10), and contact duration (10-120 min) on the removal of MV 2B was investigated using the Box-Behnken design (BBD) model. Kinetic and equilibrium dye adsorption profiles reveal that the uptake of MV 2B dye by CHA-BA/FGA is described by the pseudo-second kinetics and the Langmuir models. The thermodynamics of the adsorption process (ΔG°, ΔH°, and ΔS°) reveal spontaneous and favorable adsorption parameters of MV 2B dye onto the CHA-BA/FGA biocomposite at ambient conditions. The CHA-BA/FGA exhibited the maximum ability to absorb MV 2B of 126.51 mg/g (operating conditions: CHA-BA/FGA dose = 0.09 g/100 mL, solution pH = 8.68, and temperature = 25 °C). Various interactions, including H-bonding, electrostatic forces, π-π stacking, and n-π stacking provide an account of the hypothesized mechanism of MV 2B adsorption onto the surface of CHA-BA/FGA. This research reveals that CHA-BA/FGA with its unique biocomposite structure and favorable adsorption properties can be used to remove harmful cationic dyes from wastewater.

The first novel aspect of this research work comes from the utilization of food-grade algae which contains various types of negative functional groups hydroxyl, carboxyl, and phosphate to modify a cationic biopolymer (Chitosan) to improve its adsorptive property toward removal of a cationic dye such as methyl violet 2B. The second novel aspect of this research work is to use the hydrothermal process to assist the grafting of an aromatic ring of benzaldehyde into the polymer matrix of the chitosan-food grade algae composite via a Schiff base linkage to improve its chemical stability and functionality.