Adsorption Capacity For Methyl Orange Research Articles

Competitive adsorption of anionic and cationic molecules on three activated carbons derived from agroindustrial waste

This study examined the feasibility of sugarcane bagasse (sb), spent coffee-grounds (sg), and orange peel (op) activated carbons for the removal of methyl orange (MO) and methylene blue (MB). For such purpose, individual dye solutions and binary mixtures under different pH and initial concentrations were used. The study was complemented with Density Functional Theory (DFT) calculations to assess the carbon surface preference towards a specific molecule. The DFT method, using molecular descriptors, showed a potential application for predicting the order by which the carbons sorb a given set of contaminants. For the three carbon materials studied, the mono-dye experiments adsorption capacities ranged from 60 to 140 mg/g for MB and from 146 to 65 mg/g for MO at pH values of 5, 7 and 9. While the best methylene blue adsorbent was the sugarcane bagasse carbon, the orange peel carbon showed the best methyl orange adsorption capacity. Interestingly, the spent coffee-ground carbon exhibited a balanced behavior when both molecules were added separately. When the dyes were added as a mixture, the three carbons adsorbed methylene blue preferentially over methyl orange. While sb adsorbed up to 75 mg/g of MB and 10 mg/g of MO, op adsorbed 60 mg/g of MB and up to 25 mg/g of MO. The trend displayed in mono-dye systems was kept in binary systems. This is important since real wastewater systems contain mixtures with two or more pollutants. In the case of the binary mixtures, the three activated carbons can adsorb both type of dyes at concentrations up to 300 mg/L, the pH did not affect the MB adsorption, whereas MO uptake was greatly affected at pH > 7. Thus, it is important to study versatile materials obtained from organic wastes capable of removing more than one species from wastewater.

Synthesis of titanium phosphate/polypyrrole nanocomposites for removal of methyl orange from water

AbstractIn this paper, titanium (IV) phosphate (TiP), polypyrrole (PPy), and titanium (IV) phosphate‐polypyrrole (TiP/PPy) nanocomposites were synthesized for adsorption of methyl orange (MO) dye from water. X‐ray diffraction data showed the formation of pure samples with crystallite size 14.1 and 14.2 nm of TiP and TiP/PPy nanocomposite respectively. The specific surface area of TiP (77.127 m2 g−1) was higher than PPy (17.004 m2 g−1) and TiP/PPy nanocomposite (25.247 m2 g−1). The equilibrium adsorption capacity (qe) was found to be 9.801 and 30.69 mg g−1 for PPy and TiP/PPy nanocomposite respectively. The Langmuir model was successfully fitted, and the TiP/PPy nanocomposite (69.4 mg g−1) had a greater maximum adsorption capacity (qm) than PPy (51.9 mg g−1). The MO adsorption removal efficiency was dependent on the pH of the solution and was found to be 86.7% and 30.7% for TiP/PPy nanocomposite and PPy respectively at pH 4. Thermodynamics studied confirmed the spontaneous and exothermic nature of the adsorption process. The presence of common ions decreased MO adsorption capacity and the maximum decrease was found for sodium carbonate. Electrostatic interaction, π–π stacking, and hydrogen bonding were responsible for adsorption of MO dye on the TiP/PPy nanocomposite and PPy.

Ternary Metal-Alginate-Chitosan Composites for Controlled Uptake of Methyl Orange

Three ternary metal composites (TMCs) with iron nitrate, aluminum nitrate, and copper nitrate (Fe-TMC-N, Al-TMC-N, Cu-TMC-N) were synthesized and their physicochemical properties were investigated. Characterization of the TMCs was achieved by elemental analysis (XPS), infrared (IR) spectroscopy and thermogravimetric analysis (TGA). The surface charge of the TMCs was estimated from the point-of-zero-charge (PZC), which depended on the type of metal nitrate precursor. The adsorption properties of the TMCs showed the vital role of the metal center, where methylene blue (MB) is a cationic dye probe that confirmed the effects of surface charge for effective methyl orange (MO) anion dye uptake. MB uptake was negligible for Al-TMC-N and Cu-TMC-N, whereas moderate MB uptake occurs for Fe-TMC-N (26 mg/g) at equilibrium. The adsorption capacity of MO adopted the Langmuir isotherm model, as follows: Al-TMC-N (422 mg/g), Cu-TMC-N (467 mg/g) and Fe-TMC-N (42 mg/g). The kinetic adsorption profiles followed the pseudo-second order model. Generally, iron incorporation within the TMC structure is less suitable for MO anion removal, whereas Cu- or Al-based materials show greater (10-fold) MO uptake over Fe-based TMCs. The dye uptake results herein provide new insight on adsorbent design for controlled adsorption of oxyanion species from water.

Single-step synthesis and modification of CTAB-hectorite for efficient adsorption of methyl orange dye

Hectorite modified with cetyltrimethylammonium bromide (CTAB) using a single-step synthesis and modification produced an efficient adsorbent for water treatment. Characterization analysis revealed that incorporating CTAB at 5–10 wt/wt increased the basal distances and the mesopore area of hectorite. The high concentration at 20–40 wt/wt deposited CTAB on the external surface of hectorite, consequently reducing the surface area. TGA-DTG analysis revealed that the surface-bound CTAB has lower thermal stability than the interlayered CTAB. CTAB-modified hectorite (40-Hec) showed the adsorption capacity of methyl orange at 164.28 mg/g, with 98.57% removal efficiency, significantly higher than hectorite. The adsorption of methyl orange followed the pseudo-second order kinetic and the Sips models. The Sips isotherm was suitable to describe the adsorption mechanism by monolayer physisorption. For thermodynamic studies, parameters such as the Gibbs free energy (ΔG°), the enthalpy (ΔH°) and the entropy (ΔS°) revealed that the adsorption of methyl orange on CTAB-modified hectorite is a spontaneous exothermic process and affected by the entropy of adsorption.

Adsorptive Analysis of Azo Dyes on Activated Carbon Prepared from Phyllanthus emblica Fruit Stone Sequentially via Hydrothermal Treatment

The present work aims to provide insight into the role of the functional group in the adsorption of azo dyes namely, ethyl orange (EO), methyl orange (MO), and metanil yellow (MY), on the activated carbon (surface area 569 m2·g−1) prepared from Phyllanthus emblica fruit stone by low-pressure hydrothermal treatment (AC-HTPEFS). More specifically, this study would facilitate a better understanding of the involvement of different amino substituents (-CH3, -C2H5, phenyl group) on the adsorption of azo dye molecules. The experimental adsorption isotherms of the azo dyes quantified with different adsorbents and temperatures (25–45 °C) were utilized to know the effect of functional groups on dye adsorption. Additionally, the equilibrium data were analyzed by applying isotherm models (Freundlich, Langmuir, and Temkin) in order to elucidate the best-fit isotherm model and adsorption capacity, with the Langmuir model fitting the isotherms best as shown by the higher correlation coefficients obtained (0.984–0.994). The Langmuir monolayer adsorption capacities of EO, MO, and MY obtained at 25 °C were found to be 0.202, 0.187, and 0.158 mmol·g−1, respectively, which was attributed to the hydrophobicity and geometry of dye molecules. Moreover, adsorption kinetics conformed well with the pseudo-second-order model. The negative ΔG°, positive ΔH,° and positive ΔS° indicated the adsorption process to be favorable, endothermic, and increased randomness at the solid–liquid interface. Our findings indicate that the porous activated carbon from hydrothermally treated Phyllanthus emblica fruit stone exhibited a promising potential for the removal of azo dyes with rapid kinetics and high adsorption capacity. The present study could thus pave a way for future utilization of activated carbons produced via hydrothermal treatment techniques for wastewater applications.

A porous Fe‐based porphyrinic metal–organic framework for highly effective removal of organic azo‐dye

With the rapid development of the global dye industry, a series of environmental problems affecting the ecosystem and human health has been perceived. In this work, a porous porphyrin catecholate iron‐based metal–organic framework (MOF) (PorphCat‐Fe) has been prepared and evaluated for the first time for adsorptive removal of azo‐dye methyl orange (MO) pollutant from aqueous media. Consequently, various MO adsorption factors using PorphCat‐Fe MOF were studied and optimized. PorphCat‐Fe was able to remove about 98% of the pollutant from the water within 20 min in the batch experiments with maximum adsorption capacity of 232.5 mg g−1. Under optimum conditions, the limit of detection (LOD) was found to be 0.8 μg L−1. The MOF could maintain its adsorption efficiency toward MO in the real samples. The combination of electrostatic attractions, hydrophobic and π–π interactions, and iron‐organic coordination bonding make PorphCat‐Fe able to show the superior MO adsorption capacity. Remarkably, the removal efficiency of MO was nearly unchanged after five regeneration sequences on PorphCat‐Fe. This effort offers the ability for application of MOFs beyond metal‐carboxylate linkers in wastewater remediation.

Fast and efficient removal of dyes and Cr(VI) ion from wastewater using halloysite nanotubes-covalently coated polyurethane sponges

Inspired by the mussel adhesion protein, dopamine was used to prepare polydopamine (PDA)-coated polyurethane sponge (PDA-PUS) via self-polymerization reaction. Halloysite nanotubes (HNTs) were grafted with γ-aminopropyltriethoxysilane (APTES). The new organic-inorganic hybrid adsorption material (HNTs@PUS) was fabricated by covalent link of APTES-grafted HNTs and PDA-PUS through Schiff base reaction/Michael addition. The as-prepared HNTs@PUS showed much higher mechanical stability and compressive property than polyurethane sponge (PUS). HNTs@PUS had 7.7, 7.1, 1.7 and 8.5 times adsorption capacity of PUS for Congo red (CR), Methyl orange (MO), Rhodamine 6 G (R6G) and heavy metal ion Cr(VI), respectively. HNTs@PUS had a fast adsorption rate and most of CR, MO, R6G and Cr(VI) were adsorbed by HNTs@PUS within 20 min. In addition, HNTs@PUS maintained 70.3%, 66.5%, 67.3% and 77.4% of its adsorption capacity for CR, MO, R6G and Cr(VI), respectively, after 5 cycles of regeneration. HNTs@PUS could be easily recovered to avoid secondary contamination. Besides, using HNTs@PUS as adsorbents, a continuous flow adsorption device was developed, through which anionic and cationic dyes and heavy metal ion could be continuously and effectively removed from the flowing solution. These results demonstrated that HNTs@PUS had potentially ideal attributes for use as adsorbents in the ultrafast, high efficiency and large-scale removal of anionic and cationic dyes and heavy metal ions from wastewaters. The fabrication strategy not only solved the problem of the poor recyclability and low permeability of HNTs, but also greatly improved the adsorption capacity of PUS, which might accelerate the application of natural “green” HNTs in wastewater treatment.

Adsorption of Methyl Orange from an Aqueous Solution onto a BPPO-Based Anion Exchange Membrane.

In this research, the development of a novel brominated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO)-based homogeneous anion exchange membrane (AEM) via the solution casting method was reported. Fourier transform infrared spectroscopy was used to confirm the successful development of the BPPO-based AEM. The prepared AEM showed excellent thermal stability. It exhibited an ion exchange capacity of 2.66 mg/g, a water uptake (WR) of 68%, and a linear swelling ratio of 31%. Methyl orange (MO), an anionic dye, was used as a model pollutant to evaluate the ion exchange ability of the membrane. The adsorption capacity of MO increased with the increase in contact time, membrane dosage (adsorbent), temperature, and pH while declined with the increase in initial concentration of MO in an aqueous solution and molarity of NaCl. Adsorption isotherm study showed that adsorption of MO was fitted well to the Freundlich adsorption isotherm because the value of the correlation coefficient (R2 = 0.974) was close to unity. Adsorption kinetics study showed that adsorption of MO fitted well to the pseudo-second-order kinetic model. Adsorption thermodynamics evaluation represented that adsorption of MO was an endothermic (ΔH° = 18.72 kJ/mol) and spontaneous process. The AEM presented a maximum adsorption capacity of 18 mg/g. Moreover, the regeneration of the prepared membrane confirmed its ability to be utilized for three consecutive cycles. The developed BPPO-based AEM was an outstanding candidate for adsorption of MO from an aqueous solution.

Removal of methyl orange and acid fuschin from aqueous solution by guanidinium functionalized cellulose prepared by radiation grafting

Dyeing wastewater released from dye-utilizing industries containing numerous hazardous dyes poses serious threat to environment and human beings, thus removal of dyes from wastewater is an important issue. In current work, guanidinium functionalized cellulose (GFC) was prepared by radiation emulsion grafting glycidyl methacrylate onto cellulose followed by further modification with guanidine hydrochloride. The radiation grafting and modification conditions were optimized. The GFC used for dyes removal was obtained with grafting yield of 238% at dose of 20 kGy and guanidinium group (%) of 16.49%. The adsorption behaviors towards methyl orange (MO) and acid fuschin (AF) were investigated. Adsorption kinetics was well described by pseudo-second-order kinetic mode. The adsorption isotherm was well fitted with Langmuir isotherm model. The adsorption capacity for MO and AF reached 63.25 mg/g and 120.4 mg/g, respectively. Therefore, the GFC exhibited excellent adsorption performance, which was applicable for MO and AF removal of water treatment.

One-step coprecipitation synthesis of Cl− intercalated Fe3O4@SiO2 @MgAl LDH nanocomposites with excellent adsorption performance toward three dyes

A magnetic Cl−-intercalated Fe3O4@SiO2@MgAl-Cl− LDH nanocomposite has been successfully synthesized by modified one-step salt-assisted coprecipitation process. The Fe3O4@SiO2@MgAl-Cl− LDH nanocomposite was characterized by FTIR, XRD, XPS, SEM, HRTEM, BET and VSM. The results showed that the Fe3O4@SiO2@MgAl-Cl− LDH particles possessed core (Fe3O4@SiO2) shell (Cl− -LDH) structures and magnetic properties, and Cl− anions were successfully introduced into LDH interlayers. The unique intercalated structure with week interlayer interaction of Fe3O4@SiO2@MgAl-Cl− LDH provide efficient adsorption of methyl orange (MO), Congo red (CR) and methyl blue (MB), leading to its superior performance with much higher uptake capability with the maximum adsorption capacity of MO, CR and MB reaching 733 mg·g−1, 910 mg·g−1 and 385 mg·g−1, respectively. The adsorption process could be well described by pseudo-second-order model for MO, CR and MB. The experimental data of MO and CR could be fitted better with Freundlich model, while that of MB were fitted better with Langmuir model. The adsorption process was spontaneous and exothermic for MO and MB, while spontaneous and endothermic for CR. Moreover, the adsorbent exhibits excellent stability and reusability in the regeneration cycle, and a process called ‘‘post-processing step” is proposed to effectively improve the dye removal ability of the adsorbent in reuse. This study puts forward a new thought for the development of high-performance LDH adsorbents with mesoporous and Cl− intercalation structure for the efficient and rapid removal of dyes.

Adsorption of methyl orange on ZnO supported by seawater-modified red mud

Abstract In this study, a novel adsorbent (SRM-ZnO) was prepared using zinc oxide supported on red mud in a seawater medium and was used for the adsorption of methyl orange (MO). It is expected to solve the recycling of red mud and prepare an economical adsorbent with high efficiency to adsorb dye wastewater. Material composition and morphology analyses showed that hydrotalcite compounds were attached on the surface of SRM-ZnO. The hydrotalcite compounds can increase the surface area of the modified red mud and thus increase the adsorption capacity of MO. The adsorption of MO dye on modified red mud conforms to the Temkin isotherm model and pseudo-second-order kinetic model. The adsorption behavior mainly includes physical interaction, supplemented with chemical interactions. Result also found that the adsorption of MO on SRM-ZnO is a spontaneous exothermic process.

Adsorption characteristics of assembled and unassembled Ni/Cr layered double hydroxides towards methyl orange

The lamella aggregation state of layered double hydroxides (LDHs) may affect their sorption capacity for organic compounds. The dried LDH samples (Ni/Cr LDH-FA-D and Ni/Cr LDH-H2O-D) and the undried samples (Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W) were flexibly prepared by a co-precipitation method in formamide (FA) and water, respectively. The results of X-ray diffraction (XRD) and transmission electron microscope (TEM) showed that the undried LDHs were unassembled, which had no the stacking layers but had a pseudohexagonal nanosheet lamella structure. And the unassembled LDH layers can be assembled again during the dry process. Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W showed much greater adsorption capacities towards methyl orange (MO) than Ni/Cr LDH-FA-D and Ni/Cr LDH-H2O-D, as well as shorter time to reach equilibrium. The maximum adsorption capacity of MO could be calculated to 806 mg/g and 740 mg/g for Ni/Cr LDH-FA-W and Ni/Cr LDH-H2O-W by Langmuir-type simulation. The greater adsorption capacities of unassembled LDH could be attributed to the loosen structure and much more exposed adsorption sites. It could be concluded that unassembled LDHs were an effective and conducive preparation pathway for the exploration of the adsorption sites of LDHs.

Investigation the adsorption behavior of functional carbon-based composites for efficient removing anions / cations in single and multicomponent systems

A novel pH-responsive carbon-based nano-adsorbent (MGO-CNT@β-CS-CD) for the adsorption of dyes from aqueous solution was prepared by using graphene oxide, Fe3O4, multi-walled carbon nanotubes, β-cyclodextrin and Chitosan as raw materials. The structure and adsorption mechanism of adsorbent were performed by FT-IR, SEM, Raman, TGA, VSM, XPS, BET, XRD and ICP-MS. After that, the adsorption behaviors of MGO-CNT@β-CS-CD towards dyes Methylene blue (MB), Methyl orange (MO), Congo red (CR) and Indigo Carmine (IC) were further systematically investigated. Moreover, kinetic adsorption by MGO-CNT@β-CS-CD was well fitted with the pseudo-second-order model. The adsorption isotherms indicated that the results were fitting well with the Langmuir model, the maximum adsorption capacity of MB, MO, CR and IC reached 1580.50, 269.09, 287.43 and 258.13 mg/g, respectively. Additionally, anionic dyes could be selectively adsorbed when the pH value of the anionic and cationic mixed solution was acidic, whereas, when the pH value of the solution was alkaline, MB could be adsorbed from a mixed anion-cation system. Finally, the results showed that the nanoparticle adsorbent could be used as the packing agent of the adsorption column to realize the series adsorption of anionic - cationic - anionic dye systems, which had a good industrial application prospect.

Production of chitosan nanofibers using the HFIP/acetic acid mixture as electrospinning solvent

Chitosan nanofiber mats are of interest for biotechnological purposes owing to its physical and chemical properties, nonetheless, the production of pristine chitosan nanofibrous mats is challenging due to some of these traits restrict its solubility in most common solvents, thus limiting its electrospun processability. This work presents the production of pristine chitosan electrospun nanofibers using the 1,1,1,3,3,3-Hexafluoro-2-propanol/acetic acid binary mixture as solvent. This binary solvent improves pristine chitosan spinnability and facilitates the one-step fabrication of highly stable nanofiber mats insoluble in water and aqueous media without the need for crosslinking and neutralization, which implies no need for further washing steps, no waste production, less energy consumption, reagents saving and a significant impact on reducing total processing time compared with previously reported methodologies. Moreover, the aqueous adsorption capacity of methyl orange is improved by the microarchitecture of chitosan as-spun nanofibers produced in this work compared with chitosan powder and film, confirming an essential role of the microstructure and highlighting its potential as bioadsorbent for dye removal.

Two-dimensional assembly made up of ZIF-8 particles for the high-efficient capture of the iodine and dyes

The removal of the pollutants from the environment is the need of the environmental protection. ZIF-8 is promising adsorbents, and the construction of ZIF-8 assembly is essential to boost its performance. Here, we showed the easy synthesis of two-dimensional (2D) assembly built by ZIF-8 particles (2D A-ZIF-8) for the high-efficient capture of the iodine (I2) and dyes. The assembly was synthesized by the controllable reaction of 2-methylimidazole (2-MIM) with 2D Zn-glycerol (Zn-GL) precursor. Time-dependent experiments showed the predominant replacement of GL at outer boundary and then basic plane of the precursor by 2-MIM. The assembly can be synthesized with high output and combined the advantage of large accessible surface of 2D sheets, the plentiful pores of ZIF-8 and enhanced stability of assembly, endowing the large potential as adsorbent. The high adsorption capacity of I2 (200 wt%) was achieved on A-ZIF-8, while it is about 128 wt% on traditional dodecahedronal ZIF-8. The assembly also showed the excellent adsorption capacity for methyl orange (MO) (46.3 mg g-1) and methylene blue (MB) (46.5 mg g-1) at a concentration of 50 mg L-1. It can be easily separated for reuse benefited from the large size and enhanced stability of assembly.

Adsorption mechanism study of multinuclear metal coordination cluster Zn5 for anionic dyes congo red and methyl orange: Experiment and molecular simulation

This study aimed to investigate the adsorption behaviors of congo red (CR) and methyl orange (MO) on the coordination cluster Zn5(H2Ln)6(NO3)4 (Zn5, H3Ln = 1,2-bis-(benzo[d]imidazol-2-yl)-ethenol). Due to multinuclear assembly, multinuclear Zn5 possessed higher electrostatic potential and exhibited 3-fold enhancement in removal efficiency, compared with mononuclear Zn (Zn(H3L)2, H4L = 1,2-bis-(benzo[d]imidazol-2-yl)-1,2-ethanediol). The infrared and X-ray photoelectron spectroscopy and the electrostatic potential analysis indicated that the adsorption mechanism was electrostatic interaction and ion exchange interaction. The adsorption kinetics followed both the pseudo first-order and Bangham models. The pore system analysis and Bangham model suggested that CR and MO could diffuse in the snakelike pores of Zn5. The adsorption isotherms complied with the Langmuir isotherm model, and the maximum adsorption capacities for CR and MO are 166.91 and 100.78 mg/g at room temperature. The adsorption process was spontaneous and endothermic, driven by the entropy increase. Based on this research, the multinuclear coordination clusters can be suggested as potential adsorbents for the removal of anionic dyes.

Post-synthetic modification of conjugated microporous polymer with imidazolium for highly efficient anionic dyes removal from water

• A cationic CMP-Im was synthesized by post-synthetic modification. • CMP-Im showed superior adsorption and separation capacity for anionic dyes. • The conjugation, porosity and cation benefit the adsorption results of CMP-Im . • CMP-Im can be used to prepare packed column and beads to remove anionic dyes. Water pollution caused by organic dyes is a severe environmental problem in developing society. Adsorption has been considered as a versatile and simple water-purification method. Therefore, it is desirable to develop adsorbents with high capacity and efficiency to remove dyes. In this work, through two-step post-synthetic modification to introduce imidazolium in a conjugated microporous polymer (CMP), an effective adsorbent ( CMP-Im ) was obtained to study the rational conjugated and cationic skeleton for anionic dyes removal. All these polymers exhibited inherent porous structures and high stability. CMP-Im showed Brunauer–Emmett–Teller (BET) surface area of 533 m 2 g −1 and possessed cationic framework of imidazolium unit favoring interaction with anionic guests. Due to the conjugated, cationic and porous framework, CMP-Im exhibited fast and efficient adsorption of anionic dyes such as methyl orange (MO) and Congo red (CR), and the adsorption capacity for MO and CR were 588 and 2500 mg g −1 , respectively. CMP-Im also exhibited excellent removal ability when it was used as stuffing to prepare packed column and adsorption beads. Hence, CMP-Im can be a promising candidate for dyes removal from water. This work opens up the exploration of post-synthetic CMPs and expands the application of cationic CMPs in dye adsorption.

Soft-template solvent thermal method synthesis of magnetic mesoporous carbon-silica composite for adsorption of methyl orange from aqueous solution.

A facile soft-template solvent thermal strategy was developed to prepare mesoporous carbon-silica composite (MMCS) by using furfuryl alcohol (FA) as carbon precursor, Pluronic copolymer P123 as template, hydrated iron nitrate as iron source, and teraethylorthosilicate as silicon source and it was applied for the removal of methyl orange (MO). The as-synthesized MMCS with abound of hydrophilic groups processed a high specific surface area, large pore volume, and good magnetic response. With the increased amount of FA, the surface area and functional groups increased, promoting the adsorption effect. The maximum adsorption capacity of MO on MMCS can be high to 113.1mgg-1 at pH 4 with 150mg L-1 initial MO concentration. The adsorption isotherm, kinetic, and thermodynamics were all studied and the results showed the adsorption process well fitted Langmuir adsorption isotherm and pseudo-second-order model. Additionally, it was shown that the adsorption process could not be interfered by the co-existence of PO43-, NO3-, CO32-, SO42-, and real water matrix. And the proposed adsorbent can remove MO in three practical water samples with satisfied removal rates ranging from 92.8 to 99.8%. Thus, the MMCS prepared in this study could be utilized as an alternative adsorbent for the removal of methyl orange from practical aqueous solution.

Ultralight and porous cellulose nanofibers/polyethyleneimine composite aerogels with exceptional performance for selective anionic dye adsorption

It is significant to develop new adsorbents with excellent adsorption performance and convenient operation ability for removing pollutants from wastewater owing to the growing environmental problems. In this paper, a novel ultralight aerogel-based adsorbent with highly porous structure and good mechanical integrity was fabricated based on the interaction of amine groups on polyethyleneimine (PEI) and hydroxyl groups on cellulose nanofibers (CNF), with epichlorohydrin (ECH) serving as a crosslinker. The obtained CNF/PEI aerogel showed excellent water stability in harsh conditions, fast water-activated shape recovery, and ultra-fast water transport. The adsorption capacity for methyl orange (MO) in batch can reach to1226 mg g−1 at pH 6. Furthermore, the membrane also exhibited excellent selective adsorption and filtration, and separation performance. Therefore, this paper presents a new strategy to prepare low-cost and highly efficient adsorbents to remove organic dyes from wastewater for potential practical applications.

Highly removal of anionic dye from aqueous medium using a promising biochar derived from date palm petioles: Characterization, adsorption properties and reuse studies

The present work investigates the preparation of promising biochar derived from date palm petioles powder (DPB) via a thermal treatment. DPB was characterized through various techniques to analyze the chemical (FTIR), morphological (SEM) and point of zero charges to investigate changes incorporated through the pyrolysis process. The adsorption of methyl orange (MO) onto the biochar was investigated using batch experiments according to different parameters which influence the adsorption process such as: initial dye concentration, equilibrium time, pH, and temperature. Isothermal and reuse studies of MO adsorption onto DPB were also investigated. Results of MO removal on DPB have demonstrated that the adsorption process was initial dye concentration-dependent, and equilibrium time was occurred in 60 min. The biochar presented high stability of MO adsorption capacity in a large domain of pH. Thermodynamic analysis of this process revealed that methyl orange adsorption was exothermic and spontaneous in nature. The experimental data were analyzed by pseudo-first-order, pseudo-second-order model, and the intraparticle-diffusion for kinetics and Langmuir, Freundlich, and Temkin models for isotherms. Kinetic adsorption followed the pseudo-second-order model and the intraparticle-diffusion within pores controlled the adsorption rate. The experimental data yielded good fits with in the following isotherms order: Langmuir > Temkin > Freundlich, The maximum adsorption capacity of MO on DPB was found 461 mg.g −1 . The reusability study reveals the possibility of the reuse of DPB for three (03) cycles of adsorption–desorption, a slight decrease in the ability of methyl orange adsorption has noticed with the increase of the number of adsorption–desorption cycles : 81.03 %, 67.84 %, and 51.72 %, respectively. The found results of the present study show that the biochar derived from date palm petioles have the potential to be used as a promising adsorbent for the treatment of MO dye.