Papers by LEANDRO VINICIUS ALVES GURGEL
Catalysts, 2022
This work describes the application of raw and chemically modified cellulose and sugarcane bagass... more This work describes the application of raw and chemically modified cellulose and sugarcane bagasse for ipso-hydroxylation of aryl boronic acids in environmentally friendly reaction conditions. The catalytic efficiency of five support-[Cu] materials was compared in forming phenols from aryl boronic acids. Our investigation highlights that the CEDA-[Cu] material (6-deoxy-6-aminoethyleneamino cellulose loaded with Cu) leads to the best results under very mild reaction conditions. The optimized catalytic sequence, allowing a facile transformation of boronic acids to phenols, required the mandatory and joint presence of the support, Cu2O, and KOH at room temperature. CEDA-[Cu] was characterized using 13C solid-state NMR, ICP, and FTIR. The use of CEDA-[Cu] accounts for the efficacious synthesis of variously substituted phenol derivatives and presents very good recyclability after five catalytic cycles.
Environmental Science and Pollution Research, 2021
A new one-pot synthesis method optimized by a 23 experimental design was developed to prepare a b... more A new one-pot synthesis method optimized by a 23 experimental design was developed to prepare a biosorbent, sugarcane bagasse cellulose succinate pyromellitate (SBSPy), for the removal of Cu(II) and Zn(II) from single-component aqueous solutions, in batch and continuous modes. The bi-functionalization of the biosorbent with ligands of different chemical structures increased its selectivity, improving its performance for removing pollutants from contaminated water. The succinate moiety favored Cu(II) adsorption, while the pyromellitate moiety favored Zn(II) adsorption. Sugarcane bagasse (SB) and SBSPy were characterized using several techniques. Analysis by 13C Multi-CP SS NMR and FTIR revealed the best order of addition of each anhydride that maximized the chemical modification of SB. The maximum adsorption capacities of SBSPy for Cu(II) and Zn(II), in batch mode, were 1.19 and 0.95 mmol g-1, respectively. Homogeneous surface diffusion, intraparticle diffusion, and Boyd models were used to determine the steps involved in the adsorption process. Isothermal titration calorimetry was used to assess changes in enthalpy of adsorption as a function of SBSPy surface coverage. Fixed-bed column adsorption of Cu(II) and Zn(II) was performed in three cycles, showing that SBSPy has potential to be used in water treatment. Breakthrough curves were well fitted by the Thomas and Bohart-Adams models.
Industrial Biotechnology, 2020
The objective of the study was to evaluate the pretreatment of sugarcane bagasse (SCB) with dilut... more The objective of the study was to evaluate the pretreatment of sugarcane bagasse (SCB) with diluted citric acid solution in a pressurized system and its behavior when submitted to enzymatic hydrolysis using the Cellic® CTec 3 enzyme complex, employing a Doehlert's experimental design (2³), with 5 central points (CP). The operating variables were temperature (T, °C), time (t, min) and percentage by weight of citric acid in relation to bagasse (PCA, wt%), ranging from 120 to 180°C for 20 to 90 min and 3 to 12 wt%, respectively. The pretreatments were effective in promoting changes in compositions of lignin, hemicellulose, and cellulose in all samples in relation to raw SCB. The concentrations of the glucose reached the maximum, 23.74 g/L, for the pretreated sample with temperature of 160°C, PCA 5.25 wt%, and reaction time of 20 min, while the xylose reached the maximum, 5.23 g/L, with the sample obtained in the temperature of 150°C, PCA 7.5 wt% and 55 min.
Advances in Polymer Technology, 2020
Batch and continuous adsorption of Co2+and Cu2+from aqueous solutions by oxidized sugarcane bagas... more 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‒NaNO2to 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 capacityQmaxof 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 22factorial design with spatial time and initial ...
Industrial Crops and Products, 2017
Bioethanol production from lignocellulose biomass offers a solution to current environmental chal... more Bioethanol production from lignocellulose biomass offers a solution to current environmental challenges caused by fossil fuel energy resources, while satisfying the biorefinery concept. In this study, two-stage fractionation (autohydrolysis (AH) followed by glycerol organosolv delignification (GOD)) of sugarcane bagasse (SCB) was studied as a function of temperature, time, glycerol content and liquid-to-solid (LSR) ratio using experimental designs. The effect of three different AH pretreatment severities on delignification extents (DE) of the solid fractions were also evaluated. Scanning electron microscopy was used to examine the changes in the surface of SCB pretreated by AH. Energy balances of four fractionation conditions were estimated, and the use of pure and crude glycerol in GOD was evaluated based on DE and lignin contents. A DE of ∼64% was obtained at 210.3°C, 40 min, LSR of 6.5 (v/w) and 80% (v/v) pure glycerol for GOD of SCB pretreated by AH at 175.8°C, 49 min and LSR of 5.3 (v/w), which resulted in an energetic profitability (EP) of 141.48 MJ/kg SCB. The use of crude glycerol at 80% (v/v) under the same process conditions optimized for pure glycerol also proved to be feasible (DE of ∼64% and EP of 142.67 MJ/kg SCB), widening the possibilities for its direct use in GOD of SCB pretreated by AH in a 2G bioethanol integrated plant.
Industrial Crops and Products, 2017
This study describes the use of succinylated twice-mercerized sugarcane bagasse containing adsorb... more This study describes the use of succinylated twice-mercerized sugarcane bagasse containing adsorbed Cu 2+ or Ni 2+ 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 Cu 2+ and Ni 2+ 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.
Journal of Environmental Engineering, May 1, 2009
Journal of colloid and interface science, Jan 21, 2015
This study describes the synthesis of a new chitosan derivative (C2) with zwitterionic characteri... more This study describes the synthesis of a new chitosan derivative (C2) with zwitterionic characteristics and its use for the removal of cationic species Cu(2+), Co(2+), and Ni(2+) and anionic species of Cr(6+) in a single aqueous solution. The new adsorbent was synthesized by quaternization of the amine group of chitosan and esterification of hydroxyl groups with EDTA dianhydride. These combined reactions gave both cationic and anionic characteristics to C2 with the release of quaternary ammonium groups and carboxylic groups. The capacity of C2 to adsorb Cu(2+), Co(2+), Ni(2+), and oxyanions of Cr(6+) was evaluated in a batch process with different contact times, pH values, and initial concentrations. Adsorption isotherms were best fitted to the Langmuir and Sips models. The maximum adsorption capacities (Qmax) of C2 for adsorption of Cu(2+), Co(2+), Ni(2+), and Cr(6+) were 0.698, 1.125, 0.725, and 1.910mmol/g, respectively. The ΔadsG° values were in the range from -20 to -28kJ/mol. T...
Industrial Crops and Products, 2016
This study describes, in detail, the chemical modification of sugarcane bagasse with phthalic anh... more This study describes, in detail, the chemical modification of sugarcane bagasse with phthalic anhydride to produce a carboxylate-functionalized sugarcane bagasse (SPA). The optimized modification conditions yielded SPA with a percent weight gain of 77.08% and an amount of carboxylic acid groups of 4.76 mmol/g. The SPA was characterized by PZC, FTIR, elemental analysis, TGA, and SEM-EDX. An SPA adsorbent was used to remove Co 2+ , Cu 2+ , and Ni 2+ from aqueous solution in mono-and multicomponent systems in batch mode. The adsorption kinetics followed a pseudo-second-order model. The adsorption rate constants assumed the following order: k 2,Co 2+ > k 2,Ni 2+ > k 2,Cu 2+. Four mono-and multicomponent isotherm models were used to model the adsorption data. Monocomponent data were well described by the Langmuir model, whereas bicomponent data were well described by the modified extended Langmuir and P-Factor models. The maximum adsorption capacities (Q max,mono) for the Langmuir model were 0.561, 0.935, and 0.932 mmol/g for Co 2+ , Cu 2+ , and Ni 2+ , respectively. Adsorption in bicomponent systems revealed that Cu 2+ suppressed the adsorption of Co 2+ and Ni 2+ , whereas Ni 2+ suppressed the adsorption of Co 2+. Desorption studies revealed that the SPA adsorbent could be fully desorbed with a 1 mol/L HNO 3 solution.
Industrial Crops and Products, 2015
A new carboxylated-functionalized sugarcane bagasse (STA) was prepared through the esterification... more A new carboxylated-functionalized sugarcane bagasse (STA) was prepared through the esterification of sugarcane bagasse with trimellitic anhydride. The optimized synthesis conditions yield STA with a percent weight gain of 73.9% and the number of carboxylic acid groups accounted for 3.78 mmol/g. STA was characterized by FTIR, elemental analysis, TGA, PZC, and SEM. Adsorption kinetics followed a pseudosecond-order model. The adsorption rate constant showed the following order: k 2,Ni 2+ > k 2,Cu 2+ > k 2,Co 2+. Four mono-and multi-component isotherm models were used to model the adsorption systems. Monocomponent experimental data were fitted to Langmuir and Sips models; whereas, multicomponent data were fitted to modified extended Langmuir and P-factor models. The maximum adsorption capacities (Q max,mono) obtained from the Langmuir model were 1.140, 1.197, and 1.563 mmol/g for Co 2+ , Cu 2+ , and Ni 2+ , respectively. The competitive studies demonstrated that the multicomponent adsorption capacity (Q max,multi) was smaller than Q max,mono , as a result of the interaction between the metal ions. Desorption studies showed that all metal ions could be fully desorbed from STA.
Industrial Crops and Products, 2015
In this study, four different adsorbent materials: commercial powdered activated carbon (PAC) fro... more In this study, four different adsorbent materials: commercial powdered activated carbon (PAC) from pine tree (PAC-I) and coconut shell (PAC-III) agricultural crop wastes, coal (PAC-II), and carbon nanotubes (CNT) were tested and compared for the removal of sulfamethoxazole (SMX) from spiked aqueous solutions. The kinetic, extrathermodynamic, and thermodynamic parameters for the adsorption of SMX on PACs and CNT were also determined. The results indicate that PAC-I was the best adsorbent for SMX adsorption. SMX adsorption was only favorable with PAC-I and CNT, leading to Gibbs free energies in the range of −39 to −44 kJ mol −1 and showing that the adsorption process was spontaneous in all temperature ranges (15-45 • C) tested. Langmuir model best described SMX adsorption on PAC-I and led to maximum adsorption capacity of ∼131 mg g −1 (at 25 • C), which was ∼4.6 times higher than that observed for CNT. The mechanism of SMX adsorption on PAC-I and CNT was suggested with basis on thermodynamic and extrathermodynamic parameters. The kinetic studies showed the pseudo-second-order model best described SMX adsorption, yielding k 2 values of 0.0035 and 0.0016 g mg −1 min −1 for PAC-I and CNT, respectively.
Industrial Crops and Products, 2015
This study described the anaerobic degradation of the azo dye Remazol Golden Yellow RNL (RGY-RNL)... more This study described the anaerobic degradation of the azo dye Remazol Golden Yellow RNL (RGY-RNL) using cellulose-immobilized riboflavin (MC 3) as the redox mediator. This new solid support containing immobilized riboflavin was synthesized from succinylated mercerized cellulose, and was characterized by elemental analysis, FTIR, and solid-state 13 C NMR. MC 3 was resistant to pH 2-9, and anaerobic degradation of RGY-RNL using MC 3 in the presence of anaerobic sludge yielded a zero order degradation rate constant (k 0,obs) equal to 0.189 mg/L h, which was 56% better than experiments carried out without a redox mediator. Color removal efficiency after 48 h of degradation averaged 89.4% in experiments with MC 3 and 72% without the addition of a redox mediator. These results showed that MC 3 can be used to immobilize redox mediators, allowing reduction of wastewater treatment costs.
Industrial Crops and Products, 2015
Journal of Hazardous Materials, 2010
This work describes the preparation of a new chelating material derived from wood sawdust, Manilk... more This work describes the preparation of a new chelating material derived from wood sawdust, Manilkara sp., and not only the use of a new support, but also a chemically modified sugarcane bagasse synthesized in our previous work to remove Zn 2+ from aqueous solutions and electroplating wastewater. The first part describes the chemical modification of wood sawdust and sugarcane bagasse using ethylenediaminetetraacetic dianhydride (EDTAD) as modifying agent in order to introduce carboxylic acid and amine functional groups into these materials. The obtained materials such as the modified sugarcane bagasse, EB, and modified wood sawdust, ES were then characterized by infrared spectroscopy (IR) and CHN. The second part evaluates the adsorption capacity of Zn 2+ by EB and ES from aqueous single metal solutions and real electroplating wastewater, which concentration was determined through direct titration with EDTA and inductively coupled plasma (ICP-OES). Adsorption isotherms were developed using Langmuir model. Zn 2+ adsorption capacities were found to be 80 mg/g for ES and 105 mg/g for EB whereas for the industrial wastewater these values were found to be 47 mg/g for ES and 45 mg/g for EB. Zn 2+ adsorption in the wastewater was found to be lower than in Zn 2+ spiked solution due to the competition between other cations and/or interference of other ions, mainly Ca 2+ and Cl − that were present in the wastewater.
Journal of Environmental Management, 2014
In this study sugarcane bagasse was modified with succinic anhydride and EDTA dianhydride to obta... more In this study sugarcane bagasse was modified with succinic anhydride and EDTA dianhydride to obtain SCB 2 and EB adsorbents, respectively. These adsorbents were used to remove etherdiamine, which is used for iron ore flotation from single aqueous solutions. The removal and recovery of etherdiamine is important for environmental and economic reasons due to its toxicity and high cost. The results demonstrated that adsorption of etherdiamine by SCB 2 and EB was better fitted by a pseudo-secondorder kinetic model than pseudo-first-order and Elovich models. Adsorption isotherms were better fitted by the Langmuir model rather than the Freundlich, Sips, and Temkin models. The maximum adsorption capacities (Q max) of SCB 2 and EB for etherdiamine adsorption were found to be 869.6 and 1203.5 mg/g, respectively. The calculated DG values for adsorption of etherdiamine on SCB 2 (À22.70 kJ/ mol) and EB (À19.10 kJ/mol) suggested that chemisorption is the main mechanism by which etherdiamine is removed from the aqueous solution for both adsorbents. The high Q max values showed that SCB 2 and EB are potential adsorbents for recovering the etherdiamine and treating effluents produced from iron ore flotation.
Journal of Environmental Management, 2013
In this study the adsorption of cationic dyes by modified sugarcane bagasse with EDTA dianhydride... more In this study the adsorption of cationic dyes by modified sugarcane bagasse with EDTA dianhydride (EB) was examined using methylene blue (MB) and gentian violet (GV) as model compounds in aqueous single solutions. The synthesized adsorbent (EB) was characterized by FTIR, elemental analysis, and BET. The capacity of EB to adsorb dyes was evaluated at different contact times, pH values, and initial dye concentrations. According to the obtained results, the adsorption processes could be described by a pseudo-second-order kinetic model. The adsorption isotherms were well fitted by the Langmuir model. Maximum adsorption capacities for MB and GV on EB were found to be 202.43 and 327.83 mg/g, respectively. The free energy change during adsorption of MB and GV was found to be À22.50 and À24.21 kJ/mol, respectively, suggesting that chemisorption is the main mechanism controlling the adsorption process.
Journal of Environmental Engineering, 2009
This paper describes the preparation of new adsorbents derived from sugarcane bagasse and wood sa... more This paper describes the preparation of new adsorbents derived from sugarcane bagasse and wood sawdust ͑Manilkara sp.͒ to remove zinc ͑II͒ ions from electroplating wastewater. The first part deals with the chemical modification of sugarcane bagasse and wood sawdust, using succinic anhydride to introduce carboxylic acid functions into the material. The obtained materials ͑modified sugarcane bagasse MB2 and modified wood sawdust MS2͒ were then characterized by infrared spectroscopy ͑IR͒ and used in adsorption experiments. The adsorption experiments evaluates Zn 2+ removal from aqueous single metal solution and real electroplating wastewater on both batch and continuous experiments using fixed-bed columns prepared in laboratorial scale with the obtained adsorbents. Adsorption isotherms were then developed using Langmuir model and the Thomas kinetic model. The calculated Zn 2+ adsorption capacities were found to be 145 mg/ g for MS2 and 125 mg/ g for MB2 in single metal aqueous solution, whereas for the industrial wastewater these values were 61 mg/ g for MS2 and 55 mg/ g for MB2.
Industrial Crops and Products, 2014
Liquid hot water (LHW) pretreatment associated with high pressure carbon dioxide (HP-CO 2) was ev... more Liquid hot water (LHW) pretreatment associated with high pressure carbon dioxide (HP-CO 2) was evaluated as a potential green pretreatment technology for extraction of hemicelluloses from depithed sugarcane bagasse to produce fermentable sugars. Developing a technology based on the use of low cost, non-corrosive, and recoverable chemicals as CO 2 can result in a more efficient and economic process. In this study, depithed sugarcane bagasse was treated with LHW and HP-CO 2 at milder temperatures in comparison with LHW pretreatment alone. To assess the effects of varying pretreatment operational conditions on extraction of xylo-oligosaccharides and xylose release with cellulose preservation a central composite design (CCD) of experiments was used. The pretreatments were carried out at temperatures ranging from 93.8 • C (8.62 MPa) to 136.2 • C (12.96 MPa) and times from 17.6 to 102.4 min with a liquidto-solid ratio of 12:1. The maximum xylan and xylose concentrations were achieved by treating depithed bagasse at 100 • C for 30 min and 115 • C for 60 min, respectively. At these conditions the amount of xylan equivalent ranged 10-12 g/L. At 115 • C for 60 min, the cellulose preservation achieved 97.2%. The obtained results showed that HP-CO 2 proved to be an efficient hydrolysis agent. Samples of LHW-HP-CO 2 pretreated bagasse were tested for enzymatic digestibility. Depithed bagasse pretreated at 115 • C for 60 min after enzymatic hydrolysis had a glucose yield of 30.43 g/L and a cellulose conversion of 41.17%.
Industrial Crops and Products, 2013
This study describes the applicability of two chemically modified sugarcane bagasses containing e... more This study describes the applicability of two chemically modified sugarcane bagasses containing either adsorbed Co 2+ or Cr 3+ ions as heterogeneous catalysts for the autooxidation of monoterpenes. The main objective was to investigate new uses for these adsorbent materials which had been previously employed for treatment of aqueous solutions or effluents containing metals such as Co 2+ and Cr 3+. The adsorption efficiency of Co 2+ and Cr 3+ on SCB2 and EB was evaluated by adsorption isotherms and other techniques such as XRD, ICP-AES and TGA. Catalytic activity of the four new catalysts, SCB2-Co, SCB2-Cr, EB-Co, and EB-Cr, were assessed in the oxidation reaction of -citronellol(1), (+)-limonene(2), and (−)--pinene(3) in a free solvent system. Results obtained demonstrated that these materials were promising catalysts for the oxidation of monoterpenes. Reactant conversion ranged from 49 to 78% as determined by GC analysis and a combined selectivity up to 59% for the oxidation products was achieved.
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Papers by LEANDRO VINICIUS ALVES GURGEL