Polyethylenimine-modified sugarcane bagasse cellulose as an effective adsorbent for removing Cu(II) from aqueous solution

Polyethylenimine-modified sugarcane bagasse cellulose (SBCMP), as a new adsorbent, was synthesized by the reaction of polyethylenimine (PEI) with sugarcane bagasse cellulose and glutaraldehyde. The adsorption of Cu(II) by SBCMP was pH-dependent, and the higher removal efficiency of Cu(II) appeared in the range of pH 3.0–6.0. The adsorption isothermal data fitted well with the Langmuir model, and the maximum adsorption capacity of SBCMP was up to 107.5 mg/g. The adsorption kinetics was best described by the pseudo-second-order kinetic. The adsorption of Cu(II) by SBCMP was unfavorable at high temperatures, and thermodynamic analyses implied that the adsorption of Cu(II) by SBCMP was an exothermic reaction. Fourier transform infrared spectroscopy (FT-IR) combined with X-ray photoelectron spectroscopy (XPS) revealed that Cu(II) adsorption on SBCMP mainly controlled by the nitrogen atoms of  NH group in PEI. The results of regeneration cycles showed that SBCMP was suitable for reuse in the adsorption of Cu(II) from aqueous solution. These experimental results suggested that SBCMP is expected to be a new biomass adsorbent with high efficiency in removing Cu(II) from wastewater.     

Walnut shell supported nanoscale Fe0 for the removal of Cu(II) and Ni(II) ions from water

The walnut shell supported nanoscale zero‐valent iron (walnut‐nZVI) was prepared from sodium borohydride, iron(II) chloride tetrahydrate, and walnut shell by liquid phase chemical reduction and characterized by FTIR, TEM, and XRD. The composites were tested as adsorbent for the removal of Cu(II) or Ni(II) ions. The equilibrium data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich, which revealed that Langmuir isotherm was more suitable for describing Cu(II) and Ni(II) ions adsorption than the other two isotherm models. The results indicated that the maximum adsorption capacity was higher than some other modified biomass waste adsorbents under the proposed conditions, were 458.7, 327.9 mg g^?1 for Cu(II) or Ni(II). The adsorption kinetics data indicated that the adsorption fitted well with the pseudo‐second‐order kinetic model. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43304.     

Improved synthesis of a branched poly(ethylene imine)‐modified cellulose‐based adsorbent for removal and recovery of Cu(II) from aqueous solution

This study focuses on an improved synthesis of a branched poly (ethylene imine) (PEI)‐modified cellulose‐based adsorbent (Cell‐g‐PGMA‐PEI). We aim to improve the adsorbent capacity by reducing side reaction of epoxide ring opening during graft copolymerization of glycidyl methacrylate (GMA) onto cellulose which increases the content of epoxy groups, anchors to immobilize branched PEI moieties. FTIR spectra provided the evidence of successful graft copolymerization of GMA onto cellulose initiated by benzoyl peroxide (BPO) and modification with PEI. The amount of epoxy groups of Cell‐g‐PGMA was 4.35 mmol g^?1 by epoxy titration. Subsequently, the adsorption behavior of Cu(II) on cell‐g‐PGMA‐PEI in aqueous solution has been investigated. The data from the adsorption kinetic experiments agreed well with pseudo‐second‐order model. The adsorption isotherms can be interpreted by the Langmuir model with the maximum adsorption capacity of 102 mg g^?1 which was largely improved compared with the similar adsorbent reported. The dynamic adsorption capacity obtained from the column tests was 119 mg g^?1 and the adsorbent could be regenerated by HCl of 0.1 mol L^?1. Results indicate that the novel pathway for the synthesis of Cell‐g‐PGMA‐PEI exhibits significant potential to improve the performance of adsorbents in removal and recovery of Cu(II) from aqueous solution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Removal of Cd2+, Cu2+, Ni2+, and Pb2+ ions from aqueous solutions using tururi fibers as an adsorbent

This work investigates the removal of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ ions from aqueous solutions using tururi fibers as an adsorbent under both batchwise and fixed‐bed conditions. It was found that modification of the tururi fibers with sodium hydroxide increased the adsorption efficiencies of all metal ions studied. The fractional factorial design showed that pH, adsorbent mass, agitation rate, and initial metal concentration influenced each metal adsorption differently. The kinetics showed that multi‐element adsorption equilibria were reached after 15 min following pseudo‐second‐order kinetics. The Langmuir, Freundlich, and Redlich–Peterson models were used to evaluate the adsorption capacities by tururi fibers. The Langmuir model was found to be suitable for all metal ions. Breakthrough curves revealed that saturation of the bed was reached in 160.0 mL with Cd²⁺ and Cu²⁺, and 52.0 mL with Ni²⁺ and Pb²⁺. The Thomas model was applied to the experimental data of breakthrough curves and represented the data well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40883.     

Functionalized galactoglucomannan‐based hydrogels for the removal of metal cations from aqueous solutions

New types of hydrogels derived from O‐acetyl galactoglucomannan (AcGGM) hemicellulose have been synthesized and characterized. The objective of this work was to analyze the sorption capacity (S) of three types of hydrogels containing AcGGM derivatives incorporated into the carboxylic groups of the polymer chain in the AA hydrogel, sulfonic groups in the APA hydrogel, and amide groups in the acrylamide (Aam) hydrogel. These hydrogels are capable of interacting and removing ions such as cadmium [Cd(II)], copper [Cu(II)], lead [Pb(II)], nickel [Ni(II)], and zinc [Zn(II)]. The results show that AA and Aam hydrogels had a lower sorption capacity of ions compared to the APA hydrogel, which had a high sorption capacity. The maximal sorption capacity was determined by the successive enrichment method, obtaining Pb(II) amount of 48.3 mg/g of AA hydrogel, 65.8 mg/g of APA hydrogel, and 40.8 mg/g of Aam hydrogel. Hence, Pb(II) ions are greatly retained by the three hydrogels. These results are promising for the development of new materials with potential applications in metal ion removal. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44093.     

Phosphorylated cellulose/electrospun chitosan nanofibers media for removal of heavy metals from aqueous solutions

Contamination of water resources by toxic heavy metals has significant impacts on environmental and human health. Their removal from aqueous media is essential to ensure water sustainability and to provide safe freshwater availability to population. Electrospun chitosan (CS) nonwoven mats are efficient at removing heavy metals from aqueous media. However, they suffer from low permeability and low-mechanical strength. They are also unable to remove contaminants in a nonselective way. A bilayer sorbent media made of a porous phosphorylated cellulose substrate covered by electrospun CS nanofibers was developed to overcome those weaknesses. The hydrophilic composite shows good water permeability and mechanical strength with appropriate thermal and chemical characteristics. Adsorption tests with Cd(II) indicate that pseudo-second order and Langmuir models best fitted experimental data, with a maximum adsorption capacity of 591 mg/g at 25°C. Adsorption with multielement samples containing Cr(VI), Cu(II), Cd(II), and Pb(II) also reveal their capability to remove them in a selective way. This mechanically resistant, hydrophilic, and permeable adsorbent media was able to capture both cationic and anionic metallic contaminants.     

Bio‐sorbents from cassava waste biomass and its performance in removal of Pb2+ from aqueous solution

Cassava xanthogenate and their derivatives, as adsorbents to remove Pb²⁺ from aqueous solution, are studied based upon orthogonal factorial design. The structural and thermal properties, adsorption performance as well as equilibrium‐kinetics are comprehensively investigated with multiple tools, such as Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and UV–visible spectrum technique. The influence of multiple parameters, including initial Pb²⁺ concentrations, compositions, pH values, and temperatures, on the adsorption performance is emphasized. The crosslinked cassava xanthogenate serves as an effective bio‐sorbent to remove Pb ions from aqueous solution, allowing regeneration in dilute acid solution. The findings in this study are beneficial for the development of adsorbents from cassava waste biomass and may contribute to environment recovery in “nature‐to‐nature” manner. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39780.     

Removal of Cr(VI) from aqueous solution using amino‐modified Fe3O4–SiO2–chitosan magnetic microspheres with high acid resistance and adsorption capacity

A novel, bioadsorbent material of polyethylenimine‐modified magnetic chitosan microspheres enwrapping magnetic silica nanoparticles (Fe₃O₄–SiO₂–CTS‐PEI) was prepared under relatively mild conditions. The characterization results indicated that the adsorbent exhibited high acid resistance and magnetic responsiveness. The Fe₃O₄ loss of the adsorbent was measured as 0.09% after immersion in pH 2.0 water for 24 h, and the saturated magnetization was 11.7 emu/g. The introduction of PEI obviously improved the adsorption capacity of Cr(VI) onto the adsorbent by approximately 2.5 times. The adsorption isotherms and kinetics preferably fit the Langmuir model and the pseudo‐second‐order model. The maximum adsorption capacity was determined as 236.4 mg/g at 25°C, which was much improved compared to other magnetic chitosan materials, and the equilibrium was reached within 60 to 120 min. The obtained thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption process. Furthermore, the Cr(VI)‐adsorbed adsorbent could be effectively regenerated using a 0.1 mol/L NaOH solution, and the adsorbent showed a good reusability. Due to the properties of good acid resistance, strong magnetic responsiveness, high adsorption capacity, and relatively rapid adsorption rate, the Fe₃O₄–SiO₂–CTS‐PEI microspheres have a potential use in Cr(VI) removal from acidic wastewater. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43078.     

Preparation of cellulose adsorbents with ionic liquid and pore expansion for chromatographic applications

Chromatography is a widely used technique in protein separation, and the adsorbents are essential to separate target proteins from raw mixtures. In this study, porous cellulose beads were prepared with a direct dissolution of microcrystalline cellulose (MCC) using an ionic liquid solvent 1‐butyl‐3‐methylimidazolium chloride. Pore expanding agents (cassava starch and cyclohexane) were added in MCC solutions to change the pore structure of the cellulose beads. The results showed that the mean pore size of cellulose beads increased after the application of pore expanding agents, whereas the wet density and the specific surface area were decreased. Residence time distribution studies indicated that the beads prepared with the addition of cyclohexane had the best performance for a series of molecules with different molecular weights. The cellulose beads were coupled with diethylaminoethyl and the adsorption properties with bovine serum albumin as a model protein showed that the beads prepared with cyclohexane had the best protein adsorption capability. The chromatographic results demonstrated that ionic liquids are effective solvents for cellulose dissolution and pore expanding agents can be used to enhance the pore structure of cellulose beads. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40060.     

Study on quaternary ammonium modified tentacle‐type cellulose beads and its adsorption for

A novel anion exchange resin based on cellulose has been prepared to adsorb for the urgent demand of silver and the high toxicity of metal‐cyanide complexes. Quaternary ammonium groups were grafted onto cellulose beads as main active sites in tentacle‐type through a series of chemical reactions. The substitution degree of each reaction was determined to be about 0.854, 2.125, and 2.899 mmol g^?1, respectively. The resin exhibited excellent spherical shape with microporous structure by the observation of optical microscopy and scanning electron microscope. Moreover, the adsorption experiments demonstrated the adsorption was fast in alkaline condition. Fitting the data into isotherm and kinetic models gave the conclusion that the adsorption behavior matched better with Langmuir model and pseudo‐second‐order kinetic in initial time followed pseudo‐first‐order kinetic model in later phase. The equilibrium adsorption capacity was determined to be 3.016 mmol g^?1. With the advantages of high capacity, short equilibrium time, and alkaline resistance, the resin would be considered to a top‐priority adsorbent for the separation of . © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40987.     

Cellulose filter coated with m‐aramid for water disinfection

Cellulose filters were dipped and padded with m‐aramid dissolved in N,N‐dimethylacetamide followed by coagulation in distilled water. The coated filters were then chlorinated in a hypochlorite solution. The liquid permeability of the m‐aramid‐coated cellulose filters was examined. The resulting chlorinated and unchlorinated filters were assessed for their ability to disinfect contaminated water. The chlorinated m‐aramid‐coated cellulose filter produced 5 log reductions of Escherichia coli and Staphylococcus aureus, which was much higher than that observed on the unchlorinated m‐aramid‐coated cellulose filter. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Evaluation of new chemically modified coconut shell adsorbents with tannic acid for Cu (II) removal from wastewater

The adsorption of Cu (II) from aqueous solutions using coconut shell modified powder was investigated in batch experiments. The surface charge of the adsorbent was determined. The points of zero charge (PZC) of the adsorbents (pH_PZC) were 4.5, 2.0, and 2.0 to raw coconut (RC), raw coconut alkalized (RCA), and coconut shell modified with tannic acid (TCA) adsorbent, respectively. Batch experiments were performed under kinetic and equilibrium conditions. The kinetic data were analyzed using a pseudo second‐order, and Elovich equation. Adsorption equilibrium data were investigated using the Langmiur, Freundlich, Temkin, and Dubinin–Raduschevich (D–R) isotherm models. It has been found that chemically modified coconut shell (TAC) affected performance when compared with unmodified coconut shell (RC). Kinetic studies showed that the adsorption followed a pseudo‐second‐order rate model. Biosorption kinetics of Cu(II) on the adsorbent TCA was rapid such that almost 90% of Cu(II) were adsorbed within 80 min. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40744.     

Physical and tensile properties of epoxy laminated magnetic bacterial cellulose nanocomposite films

Despite many potential applications, the adverse impacts of magnetic nanoparticles on the tensile properties of magnetic cellulose papers and films are well established. On the other hand, water absorption and thickness swelling of cellulose materials are important limiting factors in many engineering applications. These challenges caused limited applications of magnetic cellulose nanocomposites. The aim of this study is to examine the possibility of modifying the physical and mechanical behaviors of magnetic bacterial cellulose films by epoxy resin lamination. Results showed that the tensile modulus and strength of the magnetic bacterial cellulose film, respectively, increased about 280% and 240% after epoxy lamination while they maintained their desirable magnetic and flexibility properties. Furthermore, the water absorption and thickness swelling of the epoxy laminated magnetic nanocomposite films, respectively, improved about 43% and 42%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45118.     

Parameterization of classical nonpolarizable force field for hydroxide toward the large-scale molecular dynamics simulation of cellulose in pre-cooled alkali/urea aqueous solution

The empirical force fields (FFs) based on molecular dynamics (MD) simulation studying the dissolution mechanism of cellulose in cold alkali solution suffers the lacking of reliable classical FFs for hydroxide. By a simple adjustment, we transferred one available polarizable force field (FF) of hydroxide into a nonpolarizable one and combined it with GORMOS FF. Simulation based on these parameters provided accurate hydration spheres and solution structure of hydroxide that is comparable to the polarizable one, providing an opportunity for the large-scale MD simulation of the long cellulose chain in alkali/urea system for the study of dissolution and regeneration as well as mercerization process.     

Facile preparation of EDTA‐functionalized chitosan magnetic adsorbent for removal of Pb(II)

A novel magnetic adsorbent (EDTA /chitosan/ PMMS) was facilely prepared by reacting chitosan with EDTA anhydride in presence of PEI ‐ coated magnetic microspheres. The as‐synthesized EDTA/ chitosan /PMMS was characterized by XRD, SEM, TGA, FT‐IR , and VSM, and then employed in removal of heavy metals of Pb(II) from aqueous solution. The results of the batch adsorption experiments revealed that the adsorbents had extremely high uptake capacities for Pb(II) in the pH range of 2 to 5.5, and the adsorption kinetics for EDTA/ chitosan /PMMS was consistent with the pseudo – second ‐ order kinetic model. Moreover, its equilibrium data were fitted with the Langmuir isothermal model well, which indicated that the adsorption mechanism was a homogeneous monolayer chemisorptions process. The maximum adsorption capacity of EDTA/ chitosan /PMMS for Pb(II) was found to be 210 mg g ^{? 1} at pH 4 (30 ° C), and further reuse experiments results suggested that EDTA /chitosan/ PMMS could be a potential recyclable magnetic adsorbent in the practical wastewater treatment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42384.     

Synthesis and characterization of lignin‐based cationic dye‐flocculant

Kraft lignin derivatives having cationic poly 2‐(trimethylamino)ethyl methacrylate side chains were synthesized and their property as dye‐flocculant was investigated. Lignin‐based flocculants having three types of side chain densities and three types of side chain lengths were synthesized by esterification of the lignin hydroxyl groups with bromoisobutyryl groups, atom transfer radical polymerization using 2‐(dimethylamino)ethyl methacrylate, and quaternization of the amino groups. Dye removal test was performed using three organic dyes and the obtained lignin‐based flocculants. The results indicated that the density and the length of the side chains obviously affected the flocculation behavior. When the flocculants containing the same nitrogen amount were compared, the flocculation performance was improved with the increase of the side chain length within the samples having low and middle side chain densities. In the case of the samples having high side chain density, the most efficient sample was not the sample having the longest side chain. Most of the lignin‐based flocculants removed dyes more efficiently than the poly 2‐(trimethylamino)ethyl methacrylate homopolymer. From these results, it was suggested that lignin has a potential character as the core molecule to design the high‐efficient dye‐flocculant. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46611.     

All-cellulose composites prepared by partially dissolving cellulose using NaOH/thiourea aqueous solution

All-cellulose composites (ACCs) were prepared by partially dissolving cellulose in the filter paper using NaOH/thiourea aqueous solution. The effects of dissolution time, thiourea ratio, and temperature on the properties of ACCs were investigated. ACCs were characterized by scanning electron microscope, attenuated total reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and tensile tests. The results revealed that the fibers in ACCs were tightly intertwined. The crystalline form of cellulose in ACCs was transformed from type I to type I/II mixture, and the crystallinity decreased from 77.32 to 51.40%. The tensile strength of ACCs was remarkably improved to 23.16 MPa. The results confirmed ACCs had a high potential for practical applications in the packaging field.     

Chemical and structural characterization of alkaline‐extractable hemicelluloses from various eucalyptus species

Eucalyptus species are currently one of the main feedstock for pulping and papermaking industry in China. In the present study, alkali‐extractable hemicelluloses were isolated from different eucalyptus species (Eucalyptus camaldulensis, E. urophylla × grandis, and E. urophylla × E. tereticornis) at mild conditions prior to pulping. Structural characterization of these hemicellulosic polymers based on monosaccharide, molecular weight, Fourier transform infrared, ¹H, ¹³C, and two‐dimensional heteronuclear single quantum coherence nuclear magnetic resonance analysis revealed that these alkali‐extractable polysaccharides shared the common structure composed of the (1→4)‐linked‐β‐D‐xylopyranosyl backbone with 4‐O‐methyl‐α‐D‐glucuronic acid attached to O‐2 of the xylose residues. The potential structures of the alkali‐extractable hemicelluloses were proposed based on the comprehensive analysis. The well‐characterized structures of these hemicelluloses could enlarge the industrial application of these hemicelluloses from the Eucalyptus species in a biorefinery process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2390–2398, 2013     

Poly(hydroxamic acid) ligand from palm-based waste materials for removal of heavy metals from electroplating wastewater

Heavy metals pollutants are nonbiodegradable and their bioaccumulation results in detrimental environmental consequences. Therefore, it is important to effectively remove toxic heavy metal waste from industrial sewage. Thus, the main goal of this research is to synthesize an ideal cellulose-based adsorbent from palm-based waste materials (agro waste) in order to be utilized in real-life practical applications with low cost as such removing common toxic heavy metals from industrial effluents. A poly(methyl acrylate) grafted palm cellulose was synthesized via a free-radical initiation process, followed by an oximation reaction to yield poly(hydroxamic acid) ligands. The adsorption capacity (q_e) of poly(hydroxamic acid) ligands for metal ions such as copper (Cu²⁺), iron (Fe³⁺), and lead (Pb²⁺) were 325, 220, and 300 mg g⁻¹, respectively at pH 6. In addition, the X-ray photoelectron spectrometry results are to be proved the binding of metal ions, for instance, Cu(II) ions showed typically significant BEs of 932.7 and 952.0 eV corresponding to the Cu2p3/2 and Cu2p1/2 species. The heavy metal ions adsorption followed a pseudo-first-order kinetic model pathway. The adsorption capacity (q_m) is also derived from the Langmuir isotherm linear plot, which does not showed good correction coefficients. However, the results were correlated to the Freundlich isotherm model, where the R² value showed significance (>0.98), indicating that multiple layer adsorption occurs on the synthesized ligand. The synthesized polymeric ligand is an excellent adsorbent for the removal of heavy metals from the industrial wastewater. In addition, the metal analysis results showed that about 98% removal of copper and iron ions from electroplating wastewater including lead, nickel, and chromium can be removed up to 85–97%.     

Preparation and characterization of selective phenyl thiosemicarbazide modified Au(III) ion‐imprinted cellulosic cotton fibers

In this study, a novel selective Au(III) chelating surface ion imprinted fibers based on phenyl thiosemicarbazide modified natural cotton (Au‐C‐PTS) has been synthesized, and applied for selective removal of Au(III) from aqueous solutions. Batch adsorption experiments were performed with various parameters, such as contact time, pH, initial Au(III) concentration, and temperature. The kinetic studies revealed that the adsorption process could be described by pseudo‐second‐order kinetic model, while the adsorption data correlated well with the Langmuir and Freundlich models. The maximum adsorption capacities calculated from the Langmuir equation are 140 ± 1 mg g^?1 and 72 ± 1 mg g^?1 at pH 5 for both Au‐C‐PTS and NI‐C‐PTS, respectively. The estimated thermodynamic parameters (Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy change (ΔS°)) indicated the spontaneity and exothermic nature of the adsorption process. Furthermore, the selectivity study revealed that the ion imprinted fibers was highly selective to Au(III) compared with Cu(II), Cd(II), Hg(II), and Fe(III). The adsorbent was successfully regenerated with a 0.1M HNO₃ solution. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40769.