Ion exchange properties of carboxylated bagasse

Bagasse fibers were chemically modified with the aim to prepare lignocellulosic materials that have the ability to remove heavy metal ions from waste water. Three different reactions were used for the modification: etherification using monochloroacetic acid, esterification using succinic anhydride, and oxidation using sodium periodate and sodium chlorite. Bagasse was crosslinked using epichlorohydrin before chemical modification to avoid loss of its constituents during the chemical modification or application. The structure of the prepared derivatives was proofed using Fourier transform infrared and chemical methods. The ability of the prepared bagasse cation exchangers to adsorb heavy metal ions (Cu²⁺, Ni²⁺, Cr³⁺, Fe³⁺), on a separate basis or in a mixture of them, at different metal ion concentration was tested. Thermal stability of the different bagasse derivatives was studied using thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1399–1404, 2006     

Preparation and characterization of cation exchangers from agricultural residues

Cation‐exchange systems were prepared by phosphorylation of some lignocellulosic materials, namely, rice straw, cotton stalks, and bagasse. The effect of the particle size of the lignocellulosic materials as well as their chemical constituents on the phosphorylation process was studied by the determination of the phosphorus content of the prepared ion‐exchange material. Phosphorus was determined using inductively coupled plasma atomic emission spectrometry. Optimization of the phosphorylation reaction was achieved by studying the effect of the different experimental parameters, namely, the reaction time, temperature, and amount of phosphorus oxychloride added, on the phosphate content of the reaction product. The treatment of the lignocellulosic material with sodium hydroxide was found to improve its phosphorylation. The cation‐exchange efficiency of the produced phosphated material toward Cd²⁺, Co²⁺, Cr³⁺, Cu²⁺, Fe³⁺, Ni²⁺, Pb²⁺, and Zn²⁺ was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 792–800, 2002     

Differential adsorption of heavy metal ions by cotton stalk cation‐exchangers containing multiple functional groups

Esterification of cotton stalks with chlorosulfonic acid, phosphorus oxychloride, and their mixture was carried out with the aim to prepare cation exchangers for the removal of heavy metal ions from industrial waste water. Elemental analysis, Fourier transform infrared (FTIR) analysis, and sodium ions binding capacity were used to prove the occurrence of the esterification. The efficiency of the prepared cation exchangers to remove some heavy metal ions (strontium, arsenic, copper, and nickel) at different metal ion concentration, pH, contact time, and temperature was studied. The results showed that cotton stalks that contain both phosphate and sulfonate groups (phosphosulfonated cotton stalks) showed higher adsorption of the different heavy metal ions than cotton stalks containing sulfonate or phosphate on a separate basis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4124–4132, 2006     

Effect of γ-Radiation on the Dielectric Behaviour of Some Agricultural Wastes

Abstract

Dielectric properties of some agricultural wastes e.g., cotton stalks, Cs, rice straw, Rs and bagasse, B, are studied. The chemical constituents as well as the morphology of these material play a big roll on their dielectric properties. The effect of γ-irradiation on the dielectric properties of these lignocellulosic materials is also investigated. Grafting of these raw materials with acrylamide using γ-irradiation at dose of 20 M rad is also studied. Dielectric properties of these grafted materials and its complexes with Co⁺⁺ is clarified. The mechanism of the interaction of γ-radiation with the investigated samples is also studied.     

Study of heavy metal ion absorbance by amidoxime group introduced to cellulose‐graft‐polyacrylonitrile

Amidoximated grafted cellulose was obtained by reacting hydroxylamine and cellulose‐graft‐polyacrylonitrile (C‐g‐PAN), prepared by KMnO₄/citric acid redox system, and the resultant amidoximated grafted cellulose was characterized by scanning electron microscope (SEM), solid‐state NMR, FTIR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and elemental analysis. The highest value of amidoxime content in the grafted sample was 2.42 mmol/g. The adsorption efficiencies of amidoximated grafted cellulose have been evaluated with studying different adsorption conditions. Amidoximated sample with amidoxime content 2.42 mmol/g showed high ability to adsorb the metal ions from the aqueous solutions as high as 1.7 mmol/g, 1.6 mmol/g, and 0.84 mmol/g for Co²⁺, Cu²⁺, Ni²⁺ ions, respectively, at the highest original metal ion concentration. These values are about three times larger than previous studies. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Phosphorylated cation‐exchangers from cotton stalks and their constituents

Cation‐exchangers were prepared by phosphorylation of cotton stalks and their isolated constituents (lignin, soda‐anthraquinone pulp, and bleached cellulose pulp). FTIR spectra of the phosphorylated materials showed new absorption bands at 950–1200 cm^?1 of the C? O? P bonds as a result of phosphorylation. The adsorption of different heavy metal ions (lead, copper, nickel, cobalt, chromium, and cadmium) at different metal ion concentrations (50–1500 μg) by the phosphorylated cotton stalks was studied. The adsorption of metal ions by the phosphorylated cotton stalks increased by increasing their concentration. The binding capacity of phosphorylated cellulose, lignin, and soda‐anthraquinone pulp was measured at 1000 μg metal ion concentration. The adsorption of the different heavy metal ions by phosphorylated‐lignin and ‐bleached cellulose pulp was higher than that of phosphorylated cotton stalks. Thermogravimetric analysis of the raw and phosphorylated cotton stalks showed that the resistance of the phosphorylated cotton stalks to thermal degradation was higher than that of raw cotton stalks (lower rate of weight loss), despite the lower degradation onset temperature of the phosphorylated cotton stalks. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2950–2956, 2003     

HIGH WATER ABSORBENTS FROM LIGNOCELLULOSES. I. EFFECT OF REACTION VARIABLES ON THE WATER ABSORBENCY OF POLYMERIZED LIGNOCELLULOSES

Hydrogels of 350 water-absorbency (g H₂O₂/g sample) and 900 water-keeping capacity (mL H₂O₂/g sample) were prepared from local lignocellulosic wastes. The wastes used are rice straw, sugar-cane bagasse, and cotton stalks. These hydrogels were prepared via graft–polymerization reaction using some vinyl monomers, followed by alkali hydrolysis. The effects of grafting parameters (concentration of both initiator and monomer, temperature, and time), purity of lignocellulose sample, type of monomer, pretreatment of lignocellulose, and manner of saponification reaction were examined.

The application of such polymeric materials as soil conditioners, by following the pore size distribution of sand soil, in comparison with conventional soil conditioners (e.g., natural organic fertilizer and clay), were also evaluated.     

Physical Characterization of Pulps. II. Rice Straw and Bagasse Pulps Bleached by Nonconventional Two-Stage Hydrogen Peroxide Method and Paper Sheet Making

The conventional two-stage H₂O₂ method was applied for bleaching rice straw and bagasse pulps. The pulps were bleached also by a nonconventional method: i.e., using different organic solvents with various contents in the first stage of the bleaching process. The effects of the kind and percentage of the organic solvent in the bleaching mixture on the properties of both the bleached pulps and paper sheets were studied and are discussed on the basis of the physicochemical properties of the bleaching mixtures.     

Removal of concentrated heavy metal ions from aqueous solutions using polymers with enriched amidoxime groups

Particulate and fibrous adsorbents with enriched amidoxime groups were synthesized by using a novel monomer N,N′‐dipropionitrile acrylamide. The adsorption properties of amidoximated poly(N,N′‐dipropionitrile acrylamide) [poly(DPAAm)] particles and a nonwoven fabric grafted with the same for UO₂²⁺, Pb²⁺, Cu²⁺, and Co²⁺ at high concentrations were investigated by batch process. Metal ion adsorption studies were conducted from metal ion solutions with different initial concentrations (100–1500 ppm). It was shown that particulated amidoximated poly(DPAAm) has higher adsorption capacity than amidoximated nonwoven fabrics for all metal ions, especially for uranyl ions. The results of the adsorption studies showed that the interaction between UO₂²⁺ and amidoximated groups agree with the Langmuir‐type isotherm. From the Langmuir equation, the adsorption capacities were found as 400 mg UO₂²⁺/g dry amidoximated poly(DPAAm) and 250 mg UO₂²⁺/g dry amidoximated graft polymer. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1705–1710, 2004     

Preparation and electrochemical behaviour of biomass based porous carbons as electrodes for supercapacitors — a comparative investigation

We compared the relationship of the behavior and performance of sugarcane baggase and rice straw as supercapacitor electrodes. X-ray diffraction revealed the evolution of crystallites of carbon and silica during activation at higher temperature. The morphology of the carbon samples was determined by SEM. The surface area, pore volume, and pore size distribution of carbon composites were measured. The electrochemical responses were studied by using cyclic voltammetry experiment at 25 °C in a three-electrode configuration. The specific capacitance of the sugarcane bagasse carbon electrodes was in the range 92-340 F/g, whereas for rice straw, it was found to be 56–112 F/g at scan rates of 2-3 mV/s. The sugarcane bagasse carbon exhibited better performance than rice straw carbon using H₂SO₄ as the electrolyte. However, the results clearly show that lignocellulosic wastes possess a new biomass source of carbonaceous materials for high-performance supercapacitors.     

Amidoximation of acrylonitrile radiation‐grafted onto low‐density polyethylene and its physicochemical characterization

Membranes were prepared by the direct radiation grafting of acrylonitrile onto low‐density polyethylene films. These grafted membranes were amidoximated using hydroxylamine hydrochloride in basic medium. The influence of monomer concentration and swelling behaviour of grafted membrane, amidoximated grafted membrane, and its sodium salt were also studied. Amidoximated grafted membranes and their copolymer–metal complexes of Cu(II) or Cr(III) were prepared. These membranes were characterized using different analysis techniques such as IR, UV and ESR spectrometry. The UV and ESR analyses revealed that the geometry structure for Cu(II) is square planar, while for Cr(III) it is octahedral. The amidoxime ligand was used for separating metal ions from aqueous solutions by a complexation process. The thermal stability of different membranes was investigated through TG analysis. It was found that the amidoxime‐grafted membranes possess good hydrophilic properties that may make them promising candidated for some practical applications such as the recovery of metals from their aqueous systems. © 2000 Society of Chemical Industry     

Testing of medical tablets produced with microcrystalline cellulose prepared from agricultural wastes

Microcrystalline cellulose (MCC) was prepared from bleached bagasse and rice‐straw pulps by hydrolysis using hydrochloric or sulfuric acids. Samples of the prepared MCC were analyzed using XRD, SEM, and elemental analysis. The analyses indicated that the properties of the prepared MCC were similar to commercial MCC. The MCC samples were mixed with pharmaceutical formulations to form tablets of linezolid and rosuvastatin‐calcium using two different methods; wet and direct compression. The pharmaceutical properties of the resulting tablets were investigated for: hardness, disintegration, and dissolution; in comparison with tablets produced with commercial MCC. The results showed that MCC samples from bagasse and straw pulp have properties closely similar to the commercial product. POLYM. COMPOS., 35:1343–1349, 2014. © 2013 Society of Plastics Engineers     

预处理和添加硅酸钠对草浆过氧化氢漂白的影响

对酸处理 /螯合处理过程中pH值变化以及硅酸钠的使用对麦草浆和蔗渣浆过氧化氢漂白的影响进行了研究。结果表明 ,在pH值为 3时螯合处理能够使各浆料获得最佳白度 ;硅酸钠可抑制过氧化氢漂白中纤维素的降解 ,提高纸浆粘度 ,并可使Si和Mg含量较低的蔗渣浆提高白度。     

表面活性剂耦合离子液体对稻秆酶解糖化的影响

酶解糖化是木质纤维素材料制备生物质乙醇的关键环节,因此提高稻秆等木质纤维素材料的酶解糖化效率具有重要意义。以稻秆为原料,采用表面活性剂耦合离子液体为预处理方法,考察预处理温度、时间、表面活性剂的添加比例对稻秆酶解的影响。结果表明,预处理温度为110℃、时间为60 min、表面活性剂添加比例为1%,稻秆的酶解效果最佳,与单独离子液体处理的稻秆相比,纤维转化率可提高8%～15%。同时分别通过稻秆成分分析、FTIR、XRD、SEM等对预处理前后的稻秆结构进行表征,证实预处理后酶解效率提高的合理性。     

Synthesis of a polyacrylamidoxime chelating fiber and its efficiency in the retention of palladium ions

A chelating fibrous polymer with metal complexing ability was prepared by partial conversion of the nitrile groups of melana (an acrylonitrile‐based synthetic fiber) into amidoxime groups ? C(NH₂) = NOH using a solution of 3% hydroxylamine in methanol by refluxing at 80°C. The molar ratio of NH₂OH/CN and the reaction time were adjusted to values of 0.9 and 2 h, respectively. The amidoximated polyacrylonitrile fiber with a 2.89 meq/g ion‐exchange capacity functions as an efficient chelating adsorbent for palladium ions. The pH dependence, the contact time, and the temperature of palladium ion retention from a model solution on amidoximated acrylic fiber were studied. The fibrous chelating adsorbent exhibited high affinity for palladium ions in acidic solution (pH = 2–6) at high temperature (50–60°C). The values of parameters q_m and K_L (from the Langmuir equation) determined at different temperatures of adsorption and the thermodynamic quantities ΔG, ΔH, and ΔS were calculated. The adsorbed palladium ions can be quantitatively desorbed by elution with a 0.3% hydrochloric solution of thiourea. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3730–3735, 2004     

The influences of organic residues on utilization of urea N by rice

The organic materials of vetch straw, isotopically labeled with¹⁵N and unlabeled, rice straw and¹⁵N-enriched urea were applied to rice in a greenhouse experiment to evaluate the release of available N during the decomposition of vetch material and its uptake by rice, and to measure the effect of organic materials on the efficiency of urea-N utilization by rice. Measurements were made at three sampling stages during the growth period. As expected, vetch material decomposed readily and furnished a continuous supply of N for the growth of rice, although only 18.1% of vetch-N was utilized by the rice crop. However, this was not sufficient to support the survival of all tillers until harvest. After harvest, 70% of vetch-N still remained in paddy soil. The influence of organic materials on urea-N absorption by rice became apparent at about the stage of panicle initiation. The highest urea-N uptake by rice was 42.2% in vetch straw-mixed soil. Otherwise, rice straw retarded urea-N uptake by rice. Nitrogen distribution data indicated that the vetch material would stimulate urea-N uptake by rice plants.The residual effect of vetch material was evaluated by planting Sudan grass immediately after rice was harvested. Only 4.4% of residual vetch-N was utilized in 20 weeks. This low percentage of N uptake and its low availability ratio demonstrated the poor residual effects of this leguminous material.     

Preparation of amidoximated polyester fiber and competitive adsorption of some heavy metal ions from aqueous solution onto this fiber

In this study, a fibrous adsorbent containing amidoxime groups was prepared by graft copolymerization of acrylonitrile (AN) onto poly(ethylene terephthalate) (PET) fibers using benzoyl peroxide (Bz₂O₂) as initiator in aqueous solution, and subsequent chemical modification of cyano groups by reaction with hydroxylamine hydrochloride in methanol. The grafted and modified fibers were characterized by FTIR, TGA, SEM, and XRD analysis. The crystallinity increased, but thermal stability decreased with grafting and amidoximation. The removal of Cu(II), Ni(II), Co(II), Pb(II), and Cd(II) ions from aqueous solution onto chelating fibers were studied using batch adsorption method. These properties were investigated under competitive conditions. The effects of the pH, contact time, and initial ion concentration on the removal percentage of ions were studied. The results show that the adsorption rate of metal ions followed the given order Co(II) > Pb(II) > Cd(II) > Ni(II) > Cu(II). The percentage removal of ions increased with initial ion concentration, shaking time, and pH of the medium. Total metal ion removal capacity was 49.75 mg/g fiber on amidoximated fiber. It was observed that amidoximated fibers can be regenerated by acid without losing their activity, and it is more selective for Pb(II) ions in the mixed solution of Pb‐Cu‐Ni–Co‐Cd at pH 4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adsorption of copper(II) and chromium(III) ions onto amidoximated cellulose

Chemical modification of cellulose powder is performed by successive reactions with acrylonitrile in an alkaline medium followed by aqueous hydroxylamine to prepare amidoximated cellulose. Due to complexation, the amidoxime groups immobilize heavy cations from buffered solutions at various pH values. The capacity of adsorption for Cu(II) and Cr(III) ions is related to the amount of amidoxime groups in the support and to the metal concentration of the polluted solution. The formation of a 1/1 complex is proved by the adsorption limit values. Desorption of the cations is possible by treatment with a stronger complexing agent such as ethylenediaminetetracetic acid. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1624–1631, 2000     

Amidoxime resins based on poly(acrylonitrile-co-vinylidene chloride-co-divinylbenzene) and their behavior in uptake of uranium from sea water

Amidoxime resins were derived from poly(acrylonitrile-co-vinylidene chloride-co-divinyl-benzene) beads, which were prepared by suspension polymerization of the ternary monomeric mixtures in the presence of 4-methyl-2-pentanone (MIBK) or 1,2-dichloroethane (DCE) as the diluent (porogen), in order to clarify the effect of copolymerized vinylidene chloride on properties of the resulting amidoxime resins. Pore structure analyses of the copolymers as well as of their amidoximated derivatives clarified that MIBK yields larger pores than does DCE and then the latter gives larger specific surface areas than does the former. On the other hand, chemical properties of the amidoximated resins, such as anionexchange capacities and uranyl ion uptake, were not eseentially affected by the diluent species, indicating that both MIBK and DCE as the porogen lead to the amidoxime resins with almost the same ability in recovery of uranium from sea water. The uranium recovery decreased with increase in the vinylidene chloride content, but the decrease in the recovery was minor up to the 10 mol % of vinylidene chloride. It was also clarified that the uranium recovery by the amidoxime resins containing vinylidene chloride is greatly enhanced by the alkali treatment. © 1994 John Wiley & Sons, Inc.     

稻草芦苇及其浆料制备羧甲基纤维素的比较

研究了直接由草粉或浆料制备羧甲基纤维素钠的溶剂适应性,并对产品的结构、粘度、取代度做了分析。结果表明,丙酮做溶剂时羧甲基纤维素合成的得率最高、取代度最大。草粉和草浆在丙酮溶剂中经过一次反应得到的羧甲基纤维素取代度均可达0.7以上。红外光谱表明,从草粉和从浆料制得的羧甲基纤维素样品结构上没有明显差别。以不同程度预处理的草粉为原料,可以得到取代度0.5~1.1之间的不同品质的羧甲基纤维素产品。