Facile fabrication of sulfonated porous yeast carbon microspheres through a hydrothermal method and their application for the removal of cationic dye.

Water pollution containing dyes become increasingly serious environmental problem with the acceleration of urbanization and industrialization process. Renewable adsorbents for cationic dye wastewater treatment are becoming an obstacle because of the difficulty of desorbing the dye from the adsorbent surface after adsorption. To overcome this dilemma, herein, we report a hydrothermal method to fabricate sulfonic acid modified yeast carbon microspheres (SA/YCM). Different characterization techniques like scanning electron microscopy, FTIR spectroscopy, and X-ray diffraction have been used to test the SA/YCM. Decorated with sulfonic acid group, the modified yeast carbon microspheres possess excellent ability of adsorbing positively charged materials. The removal rate of Methyl blue (MB) by renewable adsorbent SA/YCM can reach 85.3% when the concentration is 500 mg/L. The SA/YCM regenerated by HCl showed excellent regeneration adsorption capacity (78.1%) after five cycles of adsorption-desorption regeneration experiment. Adsorption isotherm and kinetic behaviors of SA/YCM for methylene blue dyes removal were studied and fitted to different existing models. Owing to the numerous sulfonic acid groups on the surface, the SA/YCM showed prominent reusability after regeneration under acidic conditions, which could withstand repeated adsorption-desorption cycles as well as multiple practical applications.

Impact of LaZnFe2O4 supported NiWO4@D400-MMT@CMS/MMA nanocomposites as a catalytic system in remediation of dyes from wastewater.

Herein, a novel nanocomposite based on lanthanum zinc ferrite and nickel tungstate was created by incorporation between (MMT-jeffamine-400) nanoparticles (NPs), chloromethyl styrene as a binder and polymethyl methacrylate monomer using solution polymerization. The as-designed nanocomposites were employed to confiscate xylenol orange "X.O" as an acidic dye and rhodamine B "RhB" as "an amphoteric dye" from colored wastewater. The impact of several parameters such as solution pH, initial dye concentration, the effect of time, and the effect of temperature was explored. The consequences indicated that the pure organoclay had negligible adsorption while that composed of organoclay with PMMA@CMS-polymer incorporated with LaZnFe2O4@NiWO4 particles detached more than 90% for xylenol orange (XO) and 93% for "rhodamine B" molecules. Electrostatic interactions are the predominant factor in the adsorption of cationic and amphoteric adsorbates, as proven by zeta-potential measurement. Additionally, the adsorbent may be regenerate and utilized up to five times with good adsorption capabilities by adding sodium hydroxide. As a result, the removal can be effectively accomplished using the nanocomposite as an adsorbent. The actual and theoretical adsorption capacity values for both dyes at all doses were closely matched, which supported the adsorption kinetics data that fit the pseudo-first order rate model well. The adsorption data's correlation values (0.995 for XO and 0.98 for RhB) indicated that both dyes' Langmuir adsorption would perform well. Furthermore, the adsorption of XO and RhB dyes on the adsorbent is confirmed to be a viable reaction by the negative values of ΔGo. The enhanced adsorbent material for the removal of amphoteric and anionic dyes from waste water is the synthesized LaZnFe2O4 supported NiWO4@D400-MMT@CMS/MMA nanocomposites, which exhibits a reusability affinity of up to five cycles.

Studies About the Effect of Halogenated Solvents on the Fluorescence Properties of 9-Aryl-Substituted Isoquinolinium Derivatives - A Case Study.

It was demonstrated that 9-aryl-substituted isoquinolinium derivatives have significantly increased fluorescence quantum yields in halogenated solvents, mostly pronounced in chloroalkanes, which appears to be specific for this type of solvents. Further analysis with selected halogenated solvents revealed that the type and number of halogen substituents and the dielectric constant of the solvent have a distinct impact on the emission quantum yield. The solvent effect is explained by a solvation of the charge shift (CS) state by attractive halogen-π interactions (halogen bond), which impedes the torsional relaxation of the excited state.

Super capacity of ligand-engineered biochar for sorption of malachite green dye: key role of functional moieties and mesoporous structure.

This study synthesized a new thiomalic acid-modified rice husk biochar (TMA-BC) as a versatile and eco-friendly sorbent. After undergoing chemical treatments, the mercerized rice husk biochar (NaOH-BC) and TMA-BC samples showed higher BET surface area values of 277.1 m2/g and 305.8 m2/g, respectively, compared to the pristine biochar (BC) sample, which had a surface area of 234.2 m2/g. In batch adsorption experiments, it was found that the highest removal efficiency for malachite green (MG) was achieved with TMA-BC, reaching 96.4%, while NaOH-BC and BC exhibited removal efficiencies of 38.6% and 27.9%, respectively, at pH 8. The engineered TMA-BC exhibited a super adsorption capacity of 104.17 mg/g for MG dye at pH 8.0 and 25 °C with a dosage of 2 g/L. The SEM, TEM, XPS, and FTIR spectroscopy analyses were performed to examine mesoporous features and successful TMA-BC carboxylic and thiol functional groups grafting on biochar. Electrostatic forces, such as π - π interactions, hydrogen bonding, and pore intrusion, were identified as key factors in the sorption of MG dye. As compared to single-solution adsorption experiments, the binary solution experiments performed at optimized dosages of undesired ions, such as humic acid, sodium dodecyl sulfate surfactant, NaCl, and NaSCN, reflected an increase in MG dye removal of 2.8%, 8.7%, 5.4%, and 12.7%, respectively, which was attributed to unique mesoporous features and grafted functional groups of TMA-BC. Furthermore, the TMA-BC showed promising reusability up to three cycles. Our study indicates that mediocre biochar modified with TMA can provide an eco-friendly and cost-effective alternative to commercially accessible adsorbents.

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.

Cocos nucifera Husk Biomass as an Effective Adsorbent for Industrial Wastewater Removal: Harnessing the Power of Nature.

BACKGROUND: Rapid industrialization has polluted waterways, threatened aquatic ecosystems and endangered human health. To solve this problem, sustainable industrial practices and innovative water treatment technology must be implemented to ensure clean and safe water for future generations. METHODS: This study aimed to investigate the adsorbent capacity of Cocos nucifera husk for ineffective removal of methylene blue (MB), a cationic dye abundantly found in industrial effluent. Adsorption capacity is measured using parameters such as dye elimination percentage and polymer dosage. The Langmuir and Freundlich isotherms, adsorption kinetics (pseudo-first, pseudo-second, and second order), and intraparticle diffusion were determined to better understand the adsorption process. RESULTS: The increased dosage of cellulose fiber results in the availability of a greater number of adsorption sites and an increased surface area. However, the dye removal efficacy decreased after reaching a specific dosage of 0.6 g/L. A concentration of 0.05 g/L was most effective in eliminating Methylene blue (MB). The value of the separation factor (0.99) suggested a favorable adsorption isotherm. The reciprocal of the heterogeneity factor (-1.469) demonstrated the concentration-independent adsorption behavior of Fiber. Freundlich and Langmuir's isotherm model showed that the pseudo-second-order kinetic model demonstrated the highest level of correlation with the experimental data about the mechanism of adsorption. The Methylene blue (MB) adsorption is not limited by the intraparticle diffusion and adsorption is influenced by surface area and concentration variation of fiber as well as solvent concentration, as evidenced by low R2 value and the fact that the intraparticle diffusion plot does not intersect with the origin. CONCLUSION: The study concludes that Cocos nucifera husk can be effectively used for the treatment of wastewater.

Discerning the catalytic treatment of cationic dye wastewater in photoreactor comprising ternary (Co3+/Co2+)-embedded SnO2/ZnFe2O4 composite sensitive toward ultra-violet illumination.

Herein, magnetic (Co3+/Co2+)-integrated SnO2, SnO2/ZnFe2O4, and ZnFe2O4 composites have been prepared from triply distilled water and 30% of isopropanol in the water medium. The phase evolution, microstructure, and magnetism were investigated successfully and tested for cationic dye wastewater degradation containing Rhodamine 6G and Methylene Blue under ultra-violet irradiation. Composite spheres are attributed to efficient heterojunction interfaces between ZnFe2O4 and SnO2 semiconductors with the support of (Co3+/Co2+) nanoparticles. The results provide a simple, low-cost, environmentally friendly, and scalable method of ternary composites to degrade mixed dyes. Co3+/Co2+-implanted SnO2/ZnFe2O4 offered narrowed bandgap energy, more light absorption, diminishing electron-hole recombination, and more charge carriers toward cationic dye wastewater than the binary components. The rate constant of Rhodamine 6G degradation was observed at 0.0237 min-1, and Methylene Blue degradation was observed at 0.0187 min-1 at 90 min under UV (λ = 365 nm) irradiation. Capturing studies of various organic reactive species and mechanisms of composites was also proposed in detail.

Green Coffee Bean Extract Assisted Facile Synthesis of Reduced Graphene Oxide and Its Dye Removal Activity.

To discharge the colored effluents from industries there needs to be effective and affordable treatment options. Adsorption using reduced graphene oxide (rGO) as an adsorbent is a prominent one. In this study, green coffee bean extract (GCBE) is utilized as a safe reducing agent for the reduction of graphene oxide (GO) to synthesize rGO. The formation of rGO is confirmed by a new peak in the UV-vis spectra at 275 nm and a diffraction peak in the XRD patterns at 22°. The effective formation of rGO is further substantiated by a change in the GO peak's properties in the FTIR, EDX, and Raman spectra and a weight loss change in TGA. The SEM and TEM analyses demonstrate the effective production of the nano-sheets of rGO having exfoliated and segregated in a few layers. Furthermore, the obtained rGO exhibited outstanding efficacy in wastewater cleanup, effectively adsorbing MB as a prototype organic dye. The kinetics and isotherm study suggested that the adsorption leads by the chemisorption and monolayer formation on the homogeneous surface of rGO. The maximum adsorption capacity is found to be 89.3 mg g-1. This process offers a fresh opportunity for the economical and safe production of rGO for wastewater treatment.

Sustainable aerogels based on biobased poly (itaconic acid) for adsorption of cationic dyes.

This work reports the synthesis of poly (itaconic acid) by thermal polymerization mediated by 2,2'-Azobis(2-methylpropionamidine) dihydrochloride. Furthermore, physical hydrogels were prepared by using high molecular weight poly (itaconic acid) characterized by low dispersity and laponite RD. The hydrogels presented porous 3D network structures, with a high-water penetration of almost 2000 g/g of swelling ratio, which can allow the adsorption sites of both poly (itaconic acid) and laponite RD to be easily exposed and facilitate the adsorption of dyes. The water adsorption followed Schott's pseudo-second-order model. The mechanism of the adsorption process was investigated using 1H and 31P NMR. The hydrogel is able to fast adsorb by a combination of electrostatic interactions and hydrogen bonding by the synergic effect of the clay and poly (itaconic acid). Moreover, the prepared aerogels exhibited a fast removal of Basic Fuchsin, with an adsorption capacity of 67.56 mg/g and a high removal efficiency (~99 %). The adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm model. Furthermore, the thermodynamic parameters showed that the BF process of adsorption was spontaneous and feasible, endothermic, and followed physisorption. These results indicated that the PIA/laponite-based aerogel can be considered a promising adsorbent material in textile wastewater treatment.

Production of activated carbon from food wastes (chicken bones and rice waste) by microwave assisted ZnCl2 activation: an optimized process for crystal violet dye removal.

A major worldwide challenge that presents significant economic, environmental, and social concerns is the rising generation of food waste. The current work used chicken bones (CB) and rice (R) food waste as alternate precursors for the production of activated carbon (CBRAC) by microwave radiation-assisted ZnCl2 activation. The adsorption characteristics of CBRAC were investigated in depth by removing an organic dye (crystal violet, CV) from an aquatic environment. To establish ideal conditions from the significant adsorption factors (A: CBRAC dosage (0.02-0.12 g/100 mL); B: pH (4-10); and C: duration (30-420), a numerical desirability function of Box-Behnken design (BBD) was utilized. The highest CV decolorization by CBRAC was reported to be 90.06% when the following conditions were met: dose = 0.118 g/100 mL, pH = 9.0, and time = 408 min. Adsorption kinetics revealed that the pseudo-first order (PFO) model best matches the data, whereas the Langmuir model was characterized by equilibrium adsorption, where the adsorption capacity of CBRAC for CV dye was calculated to be 57.9 mg/g. CV adsorption is accomplished by several processes, including electrostatic forces, pore diffusion, π-π stacking, and H-bonding. This study demonstrates the use of CB and R as biomass precursors for the efficient creation of CBRAC and their use in wastewater treatment, resulting in a greener environment.

The novelty of this research work relates to converting food wastes (mixture of chicken bones and rice waste) into activated carbon via microwave assisted ZnCl₂ activation. Moreover, the produced activated carbon was successfully applied as a potential adsorbent for removal of a toxic cationic dye; namely, crystal violet (CV) from aqueous environment.

Cellulose- supported sulfated-magnetic biocomposite produced from hemp biomass: Effective removal of cationic dyes from aqueous solution.

In present study, eco-friendly sulfated cellulose-magnetic biocomposite was successfully synthesized with a simple method from hemp biomass. ATR-FTIR was used to determine chemical changes, while FE-SEM-EDS, STEM, XRD, TG/DTA, and BET techniques were employed to identify changes in morphology, elemental composition, crystal structure, and thermal degradation. Moreover, the saturation magnetization and pHpzc values of the MSHB were also determined. The effectiveness of magnetic sulfated hemp biomass (MSHB) was tested in the removal of cationic dyes from wastewater, including methylene blue (MB), crystal violet (CV), and malachite green oxalate (MGO). The adsorption all three dyes to MSHB, the pseudo-second-order kinetic model and the Langmuir model were determined to be more appropriate, and was endothermic and spontaneous from thermodynamic parameters, too. The maximum MSHB adsorption capacities were found to be 457.6, 509.3, and 1300 mg/g for MB, CV, and MGO at 298 K. With increasing temperature, it also drastically increased in capacity. The outstanding property of the MSHB is that it shows high removal performance wide pH range, even after ten cycles its high removal efficiency is still over 96 % for all three dyes and almost unaffected from dense matrix medium. These results demonstrate that MSHB is remarkable adsorbent for removing cationic dyes.

Adsorption of Safranin O Dye by Alginate/Pomegranate Peels Beads: Kinetic, Isotherm and Thermodynamic Studies.

Water pollution is regarded as a dangerous problem that needs to be resolved right away. This is largely due to the positive correlation between the increase in global population and waste production, especially food waste. Hydrogel beads based on sodium alginate (Alg) and pomegranate fruit peels (PP) were developed for the adsorption of Safranin O dye (SO) in aqueous solutions. The obtained Alg-PP beads were widely characterized. The effects of the contact time (0-180 min), initial concentration (10-300 mg/L), initial pH (2-10), adsorbent dosage (1-40 g/L) and the temperature (293-333 K) were investigated through batch tests. The data proved that the adsorption kinetics of SO reached equilibrium within 30 min and up to 180 min. The dye adsorption is concentration dependent while a slight effect of pH was observed. The adsorption data of SO onto synthesized beads follow the pseudo second-order model. The experimental data fitted very well to Langmuir model with correlation factor of 0.92 which demonstrated the favourable nature of adsorption. The maximum adsorption capacity of Alg-PP could reach 30.769 mg/g at 293 K. Calculation of Gibbs free energy and enthalpy indicated that adsorption of SO onto Alg-PP is spontaneous (negative ΔG) and endothermic (ΔH = 9.30 kJ/mol). Analysis of diffusion and mass transport phenomena were presented. The removal efficiency was found to be 88% at the first cycle and decreased to 71% at the end of the seventh cycle. The reported results revealed that the Alg-PP beads could be used as a novel natural adsorbent for the removal of high concentrated solutions of Safranin O which is a cationic dye from liquid affluents and as future perspective, it can be used to remove various pollutants from wastewater.

Utilizing Novel Lignocellulosic Material from Hart's-Tongue Fern (Asplenium scolopendrium) Leaves for Crystal Violet Adsorption: Characterization, Application, and Optimization.

In this work, a new lignocellulosic adsorbent was obtained and tested for crystal violet dye removal from water. The material was obtained from hart's-tongue fern (Asplenium scolopendrium) leaves after minimal processing, without chemical or thermal treatment. The surface of the material was characterized using a variety of techniques, including FTIR, SEM, and color analysis. The effect of various factors on the adsorption capacity was then investigated and discussed. The kinetic and equilibrium studies showed that the general-order kinetic model and the Sips isotherm are the most suitable to describe the adsorption process. The equilibrium time was reached after 20 min and the maximum calculated value of the adsorption capacity was 224.2 (mg g-1). The determined values for the thermodynamic parameters indicated physical adsorption as the main mechanism involved in the process. The Taguchi method was used to optimize the adsorption conditions and identify the most influential controllable factor, which was pH. ANOVA (general linear model) was used to calculate the percentage contribution of each controllable factor to dye removal efficiency. Analysis of all the results shows that hart's-tongue fern (Asplenium scolopendrium) leaves are a very inexpensive, readily available, and effective adsorbent for removing crystal violet dye from aqueous solutions.

Preparation of chitosan-based ternary nanocomposite hydrogel film by loading graphene oxide nanosheets as adsorbent for enhanced methylene blue dye removal.

Our objective in this study is to fabricate a novel chitosan-based ternary nanocomposite hydrogel film by incorporating graphene oxide (GO) nanosheets into a chitosan/partially hydrolyzed polyacrylamide (PHPA) network to boost adsorption efficiency through one step self-assembly process in water. Basically, H-bonding interactions drive the formation of a crosslinking network structure. The Batch adsorption experiments evaluated the hydrogel nanocomposite's MB adsorption performance. By loading GO, surface roughness, swelling percentage (from 21,200 % to 35,800 %), elastic modulus of up to 73.7 Pa, and adsorption characteristics (from 282 mg/g to 468 mg/g) were enhanced. The nanocomposite displayed outstanding thermally/pH responsiveness properties. MB adsorption equilibrium was reached after 45 min and the adsorption capacity was 476.19 mg.g-1 when the initial concentration was 100 mg/L. The MB adsorption kinetics and isotherms by the nanocomposite were well correlated by the PSO and the Langmuir models (R2 > 0.99), respectively. The loaded nanocomposite was shown to be regenerative for five cycles through desorption studies. Thermodynamic analysis indicated that MB adsorption occurred spontaneously (ΔG°: -16.47 kJ/mol, 303 K) and exothermically (ΔH°: -79.49 kJ/mol). A plausible adsorption mechanism was proposed for the nanocomposite developed for MB removal. Our results can contribute to the design and fabrication of nanocomposite adsorbents to treat wastewater.

Sorption behavior of chitosan nanoparticles for single and binary removal of cationic and anionic dyes from aqueous solution.

In this study, chitosan nanoparticles (ChNs) were used as an adsorbent for single and simultaneous uptake of cationic (methylene blue (MB)) and anionic (methyl orange (MO)) dyes. ChNs were prepared based on the ionic gelation method using sodium tripolyphosphate (TPP) and characterized by zetasizer, FTIR, BET, SEM, XRD, and pHPZC. The studied parameters that affect removal efficiency included pH, time, and dyes' concentration. The results showed that in single-adsorption mode, the removal of MB is better in alkaline pH, contrary to MO uptake which presents higher removal efficiency in acidic media. The simultaneous removal of MB and MO from the mixture solution by ChNs could be achieved under neutral conditions. The adsorption kinetic results showed that adsorption of MB and MO for both single-adsorption and binary adsorption systems comply with the pseudo-second-order model. Langmuir, Freundlich, and Redlich-Peterson isotherms were used for the mathematical description of single-adsorption equilibrium, while non-modified Langmuir and extended Freundlich isotherms were used to fit the co-adsorption equilibrium results. The maximum adsorption capacities of MB and MO in a single dye adsorption system were 315.01 and 257.05 mg/g for MB and MO, respectively. On the other hand, and for binary adsorption system, the adsorption capacities were 49.05 and 137.03 mg/g, respectively. The adsorption capacity of MB decreases in solution containing MO and vice versa, suggesting an antagonistic behavior of MB and MO on ChNs. Overall, ChNs could be a candidate for single and binary removal of MB and MO in dye-containing wastewater.

Removing of cationic dyes using self-cleaning membranes-based PVC/nano-cellulose combined with titanium aluminate.

This research used the phase inversion approach to construct polyvinyl chloride nanocellulose@titanium aluminate nanocomposite membranes (PVC/NC@TALCM) to adsorb and filter dye from wastewater. FTIR, XRD, and SEM were used to determine the adsorptive nanocomposite membrane that had been synthesized. The thermal and electrical properties measurements were carried out using a static system. The influence of several adsorbent dosages, pH, and dye concentrations on the nanocomposite membrane's adsorption ability was investigated. Using a dead-end filtration system, the PVC-NC@TALCM was evaluated as a pressure filtration membrane system. It was found that 98.6% of MB dye was removed by PVC-NC@TALCM membrane, which was loaded with 5% titanium aluminate at pH 10. The kinetic adsorption studies indicated that the adsorption of MB onto the PVC-NC@TALCM nanocomposite membrane obeys pseudo-second-order that indicates the chemosorption process. The isotherm data were described using Freundlich and Langmuir models, and the Freundlich isotherms were shown to be more closely match the experimental data than the Langmuir model. Finally, the PVC-NC@TALCM nanocomposite membrane was economical, environmentally friendly, and self-cleaning.

High-efficient and rapid removal of anionic and cationic dyes using a facile synthesized sole adsorbent NiAlFe-layered triple hydroxide (LTH).

It would be extremely momentous to familiarize a low-cost sole adsorbent NiAlFe-layered triple hydroxides (LTHs) having a strong sorption affinity towards both anionic and cationic dyes. Using the urea hydrolysis hydrothermal method LTHs were fabricated and by altering the ratio of participant metal cations the adsorbent was optimized. BET analysis revealed that the optimized LTHs possess an elevated surface area (160.04 m2/g) while TEM and FESEM analysis portrayed the stacked sheets-like 2D morphology. LTHs were employed for the amputation of anionic congo red (CR) and cationic brilliant green (BG) dye. The adsorption study showed that within 20 and 60 min, respectively, maximum adsorption capacities were achieved at 57.47 mg/g and 192.30 mg/g for CR and BG dye. Adsorption isotherm, kinetics, and thermodynamics study revealed that both chemisorptions with physisorptions were the assertive factor for the dye encapsulation. This enhanced adsorption performance of the optimized LTH for the anionic dye is attributed to its inherent anions exchange properties and new bond formation with the adsorbent skeleton. Whereas for the cationic dye, it was because of the formation of strong hydrogen bonds, and electrostatic interaction. Morphological manipulation of LTHs, formulates the optimized adsorbent LTH111, provokes the adsorbent for this elevated adsorption performance. Overall, this study revealed that LTHs have a high potential for the effectual remediation of dyes from wastewater as a sole adsorbent at a low cost.

Decoration of polylactic acid on graphene oxide for efficient adsorption of methylene blue and tetracycline.

Decorating nanomaterials on graphene oxide (GO) can enhance its adsorption capacity and removal efficiency of water pollutants. In this study, for the first time, nano-sized polylactic acid (PLA) has been successfully decorated on the surface of GO through a facile synthesis approach. The adsorptive efficiency of GO-PLA for removing methylene blue (MB) and tetracycline (TC) from an aqueous solution was examined. The characterization confirmed the successful decoration of PLA on GO nanosheets with the nano size of PLA. It was hypothesized that the PLA was decorated on the surface of GO through covalent bonding between oxygen-containing functional groups and lactide molecules. The optimum adsorption parameters determined were at the adsorbent dose of 0.5 g L-1, pH 4, contact time of 120 min, and temperature of 318 K. The pseudo-second-order kinetic model described the contaminants' adsorption behaviour, and the intraparticle diffusion model revealed that both surface adsorption and intraparticle diffusion controlled the adsorption process. Langmuir isotherm model best described the adsorption behaviour of the pollutants on GO-PLA and demonstrated the maximum monolayer uptake capacities of MB (332.5 mg g-1) and TC (223.7 mg g-1). The adsorption results indicated that the uptake capacities of GO-PLA in comparison to GO have increased by approximately 70% and 110% for MB and TC, respectively. These observations reflect the remarkable role of nano-sized PLA that enhanced the adsorption capacity due to its additional functional group and larger surface area.

Cassava bagasse as an alternative biosorbent to uptake methylene blue environmental pollutant from water.

Herein, the methylene blue (MB) biosorption from the agroindustrial residue (cassava bagasse) is reported. The cassava bagasse residue presented an irregular surface, anionic character, and low specific surface area. The experiments were performed in batch mode. The biosorption behavior was investigated through the experimental variables, initial concentration of MB, pH, and temperature. The maximum biosorption capacity (170.13 mg g-1) reached 328 K and pH 10.0. The equilibrium and kinetics were better fitted by the Sips and general order (R2 ≥ 0.997 and R2adj ≥ 0.996) models, respectively. Furthermore, the thermodynamic study revealed a spontaneous (ΔG0 < 0) and endothermic process. Finally, the results showed cassava bagasse is a potential material for biosorption dyes from the aqueous medium. In addition, the biosorbent has a low aggregate cost and high availability, which contributes to the destination of large amounts of waste and inspires engineering applications.

Sphagnum perichaetiale Hampe biomass as a novel, green, and low-cost biosorbent in the adsorption of toxic crystal violet dye.

In this study, the Sphagnum perichaetiale Hampe biomass was collected, characterized, and used as a biosorbent in the removal of crystal violet from water. The chemical and morphological results suggest that even after minimal experimental procedures, the biomass presented interesting properties regarding the adsorption of contaminants. Results of adsorption showed that the pH was not a relevant parameter and the best adsorbent dosage was 0.26 g L-1. The kinetic results presented an initial fast step and the equilibrium was reached after 180 min. For the equilibrium data, the best adjustment occurred for the Sips model, reaching a maximum adsorption capacity of 271.05 mg g-1 and the removal percentage obtained in the maximum adsorbent dosage was 97.11%. The thermodynamic studies indicated a reversible process and that the mass-transfer phenomena is governed by the physisorption mechanism. In addition to its great performance as a biosorbent, Sphagnum perichaetiale biomass also presents economic and sustainable benefits, as its production does not require costs with reagents or energy, usually used in chemical and physical activation. The reversible process indicated that the biosorbent could be reused, decreasing the costs related to the treatment of the effluents. Thus, Sphagnum perichaetiale biomass can be considered an efficient low-cost and eco-friendly biosorbent.