Anaerobic digestion of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse in UASB reactor.

In the context of a sugarcane biorefinery, sugarcane bagasse produced may be pretreated generating a solid and liquid fraction. The solid fractionmay be used for 2G bioethanol production,while the liquid fraction may be used to produce biogas through anaerobic digestion. The aimof this study consisted in evaluating the anaerobic digestion performance of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse. For this, hydrothermal pretreatmentwas assessed in a continuous upflowanaerobic sludge blanket (UASB) reactor operated at a hydraulic retention time (HRT) of 18.4 h. Process performance was investigated by varying the dilution of sugarcane bagasse hydrolysate with a solution containing xylose and the inlet organic loading rate (OLR). Experimental data showed that an increase in the proportion of hydrolysate in the feed resulted in better process performance for steps using 50% and 100% of real substrate. The best performance condition was achieved when increasing the organic loading rate (OLR) from 1.2 to 2.4 g COD/L?d, with an organic matter removal of 85.7%. During this period, the methane yield estimated by the COD removal would be 270 L CH4/kg COD.Nonetheless,when further increasing the OLR to 4.8 g COD/L?d, the CODremoval decreased to 74%, together with an increase in effluent concentrations of VFA (0.80 g COD/L) and furans (115.3 mg/L), which might have inhibited the process performance. On the whole, the results showed that anaerobic digestion of sugarcane bagasse hydrolysate was feasible and may improve the net energy generation in a bioethanol plant, while enabling utilization of the surplus sugarcane bagasse in a sustainable manner

New use for succinylated sugarcane bagasse containing adsorbed Cu2+ and Ni2+ : efficient catalysts for gas-phase n-hexane and n-heptane oxidation reactions.

This study describes the use of succinylated twice-mercerized sugarcane bagasse containing adsorbed Cu2+ or Ni2+ ions from spiked aqueous solutions (2MSBA-Cu and 2MSBA-Ni) as heterogeneous catalysts for the catalytic oxidation of n-hexane and n-heptane in gas phase. To the best of our knowledge, this is the first study in which a spent adsorbent material based on lignocellulose biomass is used in the catalytic oxidation of volatile organic compounds. The adsorbent and spent adsorbent materials were characterized by FTIR, TGA and XRD. The amount of Cu2+ and Ni2+ adsorbed on 2MSBA was 0.49 and 2.49 mmol g?1, respectively. The catalysts were active for total oxidation of n-hexane and n-heptane, even at low temperatures. 2MSBA-Cu exhibited higher catalytic activity than 2MSBA-Ni and surprisingly their performances were comparable or superior to those of some catalysts reported in the literature, including noble metal-based catalysts

Optimization of cellulose and sugarcane bagasse oxidation : application for adsorptive removal of crystal violet and auramine-O from aqueous solution.

Cellulose (Cel) and sugarcane bagasse (SB) were oxidized with an H3PO4-NaNO2 mixture to obtain adsorbent materials with high contents of carboxylic groups. The oxidation reactions of Cel and SB were optimized using design of experiments (DOE) and response surface methodology (RSM). The optimized synthesis conditions yielded Cox and SBox with 4.8 mmol/g and 4.5 mmol/g of carboxylic acid groups, respectively. Cox and SBox were characterized by FTIR, TGA, PZC and solid-state 13C NMR. The adsorption of the model cationic dyes crystal violet (CV) and auramine-O (AO) on Cox and SBox in aqueous solution was investigated as a function of the solution pH, the contact time and the initial dye concentration. The adsorption of CV and AO on Cox was described by the Elovich equation and the pseudo-first-order kinetic model respectively, while the adsorption of CV and AO on SBox was described by the pseudo-secondorder kinetic model. Adsorption isotherms were well fitted by the Langmuir and Konda models, with maximum adsorption capacities (Qmax) of 1117.8 mg/g of CV and 1223.3 mg/g of AO on Cox and 1018.2 mg/g of CV and 682.8 mg/g of AO on SBox. Desorption efficiencies were in the range of 50?52% and re-adsorption capacities varied from 65 to 81%, showing the possibility of reuse of both adsorbent materials

Data set on the bioprecipitation of sulfate and trivalent arsenic by acidophilic non-traditional sulfur reducing bacteria.

Data presented here are related to the original paper ?Simultaneous removal of sulfate and arsenic using immobilized non-traditional sulfate reducing bacteria (SRB) mixed culture and alternative low-cost carbon sources ?published by same authors (Matos et al., 2018) [1]. The data set here presented aims to facilitate this paper comprehension by giving readers some additional information. Data set includes a brief description of experimental conditions and the results obtained during both batch and semi-continuous reactors experiments. Data confirmed arsenic and sulfate were simultaneously removed under acidic pH by using a biological treatment based on the activity of a non-traditional sulfur reducing bacteria consortium. This microbial consortium was able to utilize glycerol, powdered chicken feathers as carbon donors, and proved to be resistant to arsenite up to 8.0 mg L?1. Data related to sulfate and arsenic removal efficiencies, residual arsenite and sulfate contents, pH and Eh measurements obtained under different experimental conditions were depicted in graphical format

Synthesis and application of a new carboxylated cellulose derivative. Part I : removal of Co2+, Cu2+ and Ni2+ from monocomponent spiked aqueous solution.

A new carboxylated cellulose derivative (CTA) was prepared from the esterification of cellulose with 1,2, 4-Benzenetricarboxylic anhydride. CTA was characterized by percent weight gain (pwg), amount of carboxylic acid groups (nCOOH), elemental analysis, FTIR, TGA, solid-state 13C NMR, X-ray diffraction (DRX), specific surface area, pore size distribution, SEM and EDX. The best CTA synthesis condition yielded a pwg and nCOOH of 94.5% and 6.81 mmol g 1, respectively. CTA was used as an adsorbent material to remove Co2+, Cu2+ and Ni2+ from monocomponent spiked aqueous solution. Adsorption studies were developed as a function of the solution pH, contact time and initial adsorbate concentration. Langmuir model better fitted the experimental adsorption data and the maximum adsorption capacities estimated by this model were 0.749, 1.487 and 1.001 mmol g 1 for Co2+, Cu2+ and Ni2+, respectively. The adsorption mechanism was investigated by using isothermal titration calorimetry. The values of DadsH were in the range from 5.36 to 8.09 kJ mol 1, suggesting that the mechanism controlling the phenomenon is physisorption. Desorption and re-adsorption studies were also performed. Desorption and re-adsorption efficiencies were closer to 100%, allowing the recovery of both metal ions and CTA adsorbent

Oxidized renewable materials for the removal of cobalt(II) and copper(II) from aqueous solution using in batch and fixed-bed column adsorption.

Batch and continuous adsorption of Co2+ and Cu2+ from aqueous solutions by oxidized sugarcane bagasse (SBox) and oxidized cellulose (Cox) were investigated. The oxidation reaction of sugarcane bagasse and cellulose was made with a mixture of H3PO4?NaNO2 to obtain SBox and Cox, with the introduction of high number of carboxylic acid functions, 4.5 and 4.8?mmol/g, respectively. The adsorption kinetics of Co2+ and Cu2+ on SBox and Cox were modeled using two models (pseudo-first-order and pseudo-second-order) and the rate-limiting step controlling the adsorption was evaluated by Boyd and intraparticle diffusion models. The Sips and Langmuir models better fitted the isotherms with values of maximum adsorption capacity of 0.68 and 0.37?mmol/g for Co2+ and 1.20 and 0.57?mmol/g for Cu2+ adsorption on Cox and SBox, respectively. The reuse of both spent adsorbents was evaluated. Adsorption of Cu2+ and Co2+ on SBox in continuous was evaluated using a 22 factorial design with spatial time and initial metal concentration as independent variables and and effective use of the bed as responses. The breakthrough curves were very well described by the Bohart?Adams original model and the values for Co2+ and Cu2+ were 0.22 and 0.55?mmol/g. SBox confirmed to be a promising biomaterial for application on a large scale

Adsorption of Cu(II), Cd(II), and Pb(II) from aqueous single metal solutions by succinylated mercerized cellulose modified with triethylenetetramine.

This study describes the preparation of two new chelating materials derived from succinylated mercerized cellulose (cell 1). Cell 1 was activated through two different methods by using diisopropylcarbodiimide and acetic anhydride (to form an internal anhydride) and reacted with triethylenetetramine in order to obtain cell 2 and 4. New modified celluloses were characterized by mass percent gain, concentration of amine functions, elemental analysis, and infrared spectroscopy. Cell 2 and 4 showed degrees of amination of 2.8 and 2.3 mmol/g and nitrogen content of 6.07% and 4.61%, respectively. The capacity of cell 2 and 4 to adsorb Cu2+, Cd2+, and Pb2+ ions from single aqueous solutions were examined. The effect of contact time, pH, and initial concentration of metal ions on the metal ions uptake was also investigated. Adsorption isotherms were well fitted by the Langmuir model. The maximum adsorption capacity of cell 2 and 4 were found to be 56.8 and 69.4 mg/g for Cu2+; 68.0 and 87.0 mg/g for Cd2+; and 147.1 and 192.3 mg/g for Pb2+, respectively

Removal of Ca(II) and Mg(II) from aqueous single metal solutions by mercerized cellulose and mercerized sugarcane bagasse grafted with EDTA dianhydride (EDTAD).

In a previous work, chemically modified cellulose (EMC) and sugarcane bagasse (EMMB) were prepared from mercerized cellulose (MC) and twice-mercerized sugarcane bagasse (MMB) using ethylenediaminetetraacetic dianhydride (EDTAD) as modifying agent. In this work we described in detail the modification of these materials in function of reaction time and EDTAD amount in the reaction media. The resistance of ester bond at pH 1, 2, 11, and 12 was also evaluated by FTIR. The results were used to model the hydrolysis process and a kinetic model was proposed. The modified materials (EMMB and EMC) were used to adsorb Ca2+ and Mg2+ ions from aqueous single solutions. The adsorption isotherms were developed at two pH values. These materials showed maximum adsorption capacities for Ca2+ and Mg2+ ions ranging from 15.6 to 54.1 mg/g and 13.5 to 42.6 mg/g, respectively. The modified material from sugarcane bagasse (EMMB) showed larger maximum adsorption capacities than modified material from cellulose (EMC) for both metals

Synthesis and application of a new carboxylated cellulose derivative. Part II : removal of Co2+, Cu2+ and Ni2+ from bicomponent spiked aqueous solution.

In the second part of this series of studies, the competitive adsorption of three binary systems Cu2+?Co2+, Cu2+?Ni2+ and Co2+?Ni2+ on a carboxylated cellulose derivative (CTA) was evaluated in binary equimolar (1:1) metal?ion aqueous solutions. Bicomponent adsorption studies were developed as a function of contact time and initial metal ion concentration. Bicomponent adsorption kinetic data was modeled by monocomponent kinetic models of pseudo-first- (PFO) and pseudo-second-order (PSO) and a competitive kinetic model of Corsel. Bicomponent adsorption isotherm data was modeled by the ideal adsorbed solution theory (IAST) and real adsorbed solution theory (RAST) models. The monocomponent isotherm models implemented into the IAST were the Langmuir and Sips models, whereas for the RAST model only the Langmuir model was implemented because this model provided the best prediction of the bicomponent isotherm data. The surface of the CTA adsorbent after bicomponent adsorption of metal ions was also examined by SEM-EDX. The effect of one metal ion on the adsorption capacity of another metal ion was discussed in detail with basis on the kinetic and thermodynamics parameters. The selectivity and performance of the CTA adsorbent for the removal of Cu2+, Co2+ and Ni2+ was also evaluated and discussed

Obtaining a new carboxylated derivative of microcrystalline cellulose : an easy and solvent-free synthesis.

O presente trabalho descreve a prepara??o de um novo derivado carboxilado de celulose microcristalina, usando como agente de esterifica??o o ?cido de Meldrum (2,2-dimetil-1,3-dioxano-4,6-diona), sem utiliza??o de solvente. O m?todo produziu um novo material com alto grau de funcionaliza??o. Condi??es otimizadas de s?ntese produziram celulose microcristalina modificada com ?cido de Meldrum (MCCM) com um ganho de massa de 79,9 % e 4.21 mmol/g de fun??es carbox?licas introduzidas ap?s 4 horas de rea??o usando uma propor??o de celulose microcristalina (MCC) para ?cido de Meldrum (MA) de 1:6. MCCM foi caracterizada com sucesso usando FTIR, Difra??o de Raio-X (DRX), an?lise termogravim?trica (TG) e Microscopia Eletr?nica de Varredura (MEV).A solvent-free method for the one-step preparation of a new carboxylatedmicrocrystalline cellulose (MCCM) derivative is described in the present study. The method uses as esterification agent the 2,2-dimethyl-1,3-dioxane-4,6-dione ?Meldru??s a?id) and produced a novel material with high degree of functionalization. Optimized synthesis conditions yielded a MCCM with a weight gain of 79.9% and 4.21 mmol/g of carboxylic acid functions after 4 h of reaction using a microcrystalline cellulose (MCC) to Meldru??s a?id ?MA? ratio of ?:6. MCCM ?as ?hara?terized ?ith success by FTIR, X-ray diffraction (XRD), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM)