Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

Pereira, Catarina; Neiverth, Cristhiane; Maeda, Shizuo; Guiotoku, Marcela; Franciscon, Luziane

doi:10.1590/s0100-06832011000400027

Cited by 16 publications

(3 citation statements)

References 17 publications

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“…Analysis of RO Brine's ion composition. The composition of impurities of RO Brine as feed pretreatment process is analyzed by several methods [21] [22]. Some of the impurities ions that have large amounts on RO Brine are Ca 2+ , Mg 2+ , Na 2+ , Cl -, SO4 2and K + .…”

Section: Resultsmentioning

confidence: 99%

Pretreatment Process on Reverse Osmosis Brine as Electrodialysis Feed

Taufany

Setyono

Wasi

et al. 2022

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Reverse Osmosis (RO) Brine is waste generated from the desalination process using the RO method. RO Brine is generally directly thrown back into the sea, even though it has the potential to be reprocessed because it still contains a variety of ions in it. The best method in RO Brine processing is Electrodialysis. But it has a problem of decreased membrane performance caused by the formation of fouling. The fouling problem can be overcome by doing a pretreatment process to eliminate impurities contained in RO Brine, one of which is Ca2+. The existence of Ca2+ can trigger the formation of CaSO4 deposits. Therefore, it needs excess reagent Na2CO3 with a certain amount to eliminate the whole Ca2+. Currently, it isn’t yet known the best pretreatment conditions that can eliminate impurities ions and produce high concentrations of NaCl. Pretreatment trials are needed in various variations of reagents amount to reduce impurities. The purpose of this study is to find out the best RO Brine pretreatment process that will later be used for the electrodialysis process to produce high NaCl recovery. The best results were obtained in the pretreatment process with variations NaOH excesses by 15% and Na2CO3 by 30% from the ideal stoichiometry.

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Section: Resultsmentioning

confidence: 99%

Pretreatment Process on Reverse Osmosis Brine as Electrodialysis Feed

Taufany

Setyono

Wasi

et al. 2022

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“…The following soil parameters were measured (listed in Table A3): soil particle-size analysis by modified pipette method (Staff, 1993); soil pH determined in H 2 O (2:1); available phosphorus (P) by Mehlich-1 extractant; exchangeable calcium (Ca 2+ ) and magnesium (Mg 2+ ) by 1 M KCl extractant and complexometric titration (Pereira et al, 2011); exchangeable potassium (K + ) by 0.05 M HCl extractant and atomic absorption spectroscopy determination; exchangeable aluminum (Al 3+ ) by 1 M KCl extractant and volumetric determination with 0.025 M NaOH and bromothymol blue; sulfur (S) by gravimetric analysis using HCl 1:1, aqueous solution of 1 M BaCl 2 , and BaSO 4 insoluble precipitate measurement; exchangeable acidity (H + + Al 3+ ) by 1 M KCl extractant; sum of bases = K + + Ca 2+ + Mg 2+ + Na + ; and effective cation exchange capacity (CECe), calculated as CECe = H + + Al 3+ + K + + Ca 2+ + Mg 2+ + Na + . Total soil organic carbon (SOC, in g C kg − 1 ) was determined by the Walkley-Black chromic acid wet oxidation method and calculated as SOC = soil organic matter content in g kg − 1 /1.724 (Walkley and Black, 1934).…”

Section: Soil Analyses and Calculationsmentioning

confidence: 99%

Litter and soil biogeochemical parameters as indicators of sustainable logging in Central Amazonia

Bomfim

Silva

Pereira

et al. 2020

Science of The Total Environment

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One-fourth of Brazilian Amazonia is managed for timber production, but only a few logging sites follow sustainable forest management plans (SFMPs). Amazon forests without SFMPs are susceptible to deforestation because such plans integrate the use of forest products and conservation goals by allowing selective wood extraction following regulations. It remains uncertain whether reduced-impact selective logging (17-20 m 3 ha − 1 yr − 1 of 38-70 species), typical of SFMPs, changes forest regeneration, carbon (C) stocks, and nutrient cycling. Here, we tested the hypothesis that litter and soil biogeochemical parameters serve as indicators of sustainable logging as forest regeneration, C stocks, and C-to-nutrient ratios in soil and litter become similar to those in primary forests as time elapses after logging. We used a chronosequence spanning nine years since logging to relate litter and soil (0-10, 10-30, 30-50 cm) C stocks and 12 and 15 biogeochemical parameters, respectively, canopy cover and tree seedling density (10-150 cm tall) in sustainably managed upland evergreen Amazon forests. In one unlogged and four logged stands sampled three, five, seven, and nine years after logging, we compared 15 permanent plots (three replicated 0.5 ha plots per time-since-logging category). Five biogeochemical parameters explained >80% of the variation in soil and litter among logged and unlogged stands. Litter parameters were more sensitive to logging than soil parameters, where litter C stocks and C-to-nutrient ratios increased systematically after logging. Canopy cover decreased over time and was~14% lower nine years after logging. Total seedling density did not change consistently over time but was~54% higher seven years after logging. Our data suggest that the SFMP guidelines have served the purpose of maintaining soil quality and forest regeneration. Litter and soil parameters can be useful indicators of sustainable forest management in upland evergreen forests in Central Amazonia.

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“…The calcium content leached from the catalyst to FAME was determined using a methodology adapted from the literature, 24 in which 1 mL of sample was added to 25 mL of ethanol containing 1 mL of ammonium buffer solution (ca. pH 10) composed of NH 4 Cl/NH 4 OH.…”

Section: Reusability Of the Catalystmentioning

confidence: 99%

Residue-Based CaO Heterogeneous Catalysts from Crab and Mollusk Shells for FAME Production Via Transesterification

Cardoso

Cavalcanti

Silva

et al. 2020

J. Braz. Chem. Soc.

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The production of fatty acid methyl esther (FAME) via transesterification was studied, assessing the influence of CaO heterogeneous catalysts obtained from four different fishery residues: sururu, crab, clam and mussel. Characterization and properties of the residues were obtained via thermogravimetric analysis, X-ray diffraction, X-ray fluorescence, Fourier transform infrared (FTIR) spectra, nitrogen adsorption/desorption, chemical composition and scanning electron microscopy (SEM). Catalytic activities and reaction kinetics of FAME synthesis from the transesterification of soybean oil were performed. FAME yield was determined by 1 H nuclear magnetic resonance (NMR). A higher efficiency and reaction rate were observed for the catalysts obtained from the sururu residues with 93.7% FAME yield after 3.5 h of reaction at the first usage, reducing only to 91.0% after four consecutive cycles of reuse. The best activities were assigned to the presence of SrO, to smaller particle size, higher pore volumes and the higher Ca leaching, yielding Ca-diglyceroxide which is an important active phase for transesterification.

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Complexometric titration with potenciometric indicator to determination of calcium and magnesium in soil extracts¹

Abstract: SUMMARYThis study proposes a method of direct and simultaneous determination of the amount of Ca 2+

Cited by 16 publications

References 17 publications

Pretreatment Process on Reverse Osmosis Brine as Electrodialysis Feed

Pretreatment Process on Reverse Osmosis Brine as Electrodialysis Feed

Litter and soil biogeochemical parameters as indicators of sustainable logging in Central Amazonia

Residue-Based CaO Heterogeneous Catalysts from Crab and Mollusk Shells for FAME Production Via Transesterification

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