Características principales del biocarbón derivado de restos de Theobroma cacao L. para su uso en suelos agrícolas

La incorporación de biocarbono para mejorar los suelos agrícolas está ganando popularidad, pero hay poca información sobre las propiedades del biocarbono derivado de los restos de la cosecha de cacao. En la investigación se determinaron varias características del biocarbono obtenido del proceso de pirólisis de la cáscara de las mazorcas de cacao. Los análisis realizados fueron: porcentajes de fibra lignocelulósica, análisis proximal, estructura microscópica y grupos funcionales. También se realizó con el biocarbón un ensayo de adsorción con Cd+2 mediante un sistema de recirculación con agua, con el fin de obtener las isotermas de Lang-muir y Freundlich (modelos matemáticos de adsorción de moléculas en superficies sólidas). Los contenidos fibrosos abarcaban 56,2% celulosa, 27,07% lignina y 3,15% hemicelulosa. Con 8,15% de humedad y pH 9,86 se obtuvo un promedio de 35,58% de biocarbón. La forma de los poros fue irregular, se confirmó la presencia de los grupos hidroxilo, carboxilo y carbonato. Los modelos de absorción indicaron una capacidad de adsorción máxima de 0,280 mL/g en Langmuir y una intensidad de absorción de Cd+2 de 0,06 en Freundlich. Si bien el biocarbón demostró propiedades adecuadas para suelos ácidos, su capacidad de adsorción resultó limitada en las condiciones evaluadas.

Using biochar to enhance agricultural soils is becoming more popular, but not much is known about the qualities of biochar made from cocoa crop leftovers. The study identified several traits of biochar created from cocoa pod husks through the pyrolysis method. The examination included the following evaluations: levels of lignocellulosic fibre, proximal analysis, microscopic structure, and functional groups. The Langmuir and Freundlich isotherms were evaluated through an aqueous recirculation Cd2+ adsorption assay. The fibrous contents consisted of 56.2% cellulose, 27.07% lignin, and 3.15% hemicellulose. At a moisture content of 8.15% and a pH of 9.86, 35.58% biochar was produced. The pores were not uniform in shape and contained hydroxyl, carboxyl and carbonate groups as identified. According to the isotherms, the Cd2+ that can be adsorbed is 0.280 mL/g at Langmuir, and the Cd2+ adsorption intensity is 0.06 at Freundlich. Even though the biochar had desirable properties for acidic soils, its ability to adsorb was restricted under the tested conditions.

O uso crescente do biocarvão em solos agrícolas justifica uma investigação mais aprofundada de suas propriedades menos conhecidas. Esta pesquisa concentrou-se no biocarvão produzido a partir de resíduos da colheita do cacau e teve como objetivo identificar seus atributos por meio da pirólise da casca da vagem do cacau. As análises realizadas incluíram fibra lignocelulósica, análise proximal, estrutura microscópica e grupos funcionais. As isotermas de Langmuir e Freundlich foram avaliadas por meio de um ensaio de adsorção de Cd2+ em recirculação aquosa. O conteúdo fibroso consistia em 56,2% de celulose, 27,07% de lignina e 3,15% de hemicelulose. Com um teor de umidade de 8,15% e um pH de 9,86, foram produzidos 35,58% de biochar. A estrutura porosa era irregular, indicando a presença de grupos hidroxila, carboxi-la e carbonato. As isotermas mostraram que o modelo de Langmuir tem uma capacidade máxima de adsorção (qmax) de 0,280 mL/g e uma intensidade de ad-sorção de Freundlich de 0,06 para Cd2+. Embora o biochar tenha demonstrado propriedades adequadas para uso agrícola, sua capacidade de adsorção foi limitada nas condições avaliadas.

Analysis of Safe Storage Moisture Content of Mume Flos Decoction Pieces Based on Theory of Water Activity and Water Molecular Mobility / 中国实验方剂学杂志

ObjectiveThe hygroscopic properties of Mume Flos decoction pieces were studied from the perspectives of macroscopic［water activity（Aw）］ and microscopic（water molecular mobility）， which provided a theoretical basis for the determination of the safe storage moisture content. MethodAdsorption isotherm of Mume Flos decoction pieces was obtained by static weighing method， and seven common hygroscopic models were fitted and estimated. The best model was selected according to the principle that determination coefficient（R2） was closer to 1， residual sum of squares（RSS） was closer to 0 and Akaike information criterion（AIC） was smaller. According to the optimal model， the absolute and relative safe moisture contents of Mume Flos decoction pieces at 25， 35， 45 ℃ was calculated. Low-field nuclear magnetic resonance（LF-NMR） was used to measure the water molecular mobility in the hygroscopic process of Mume Flos decoction pieces. ResultThe best model to describe the adsorption isotherm of Mume Flos decoction pieces was the Peleg model. According to the model expression， the absolute safe moisture contents of Mume Flos decoction pieces at 25， 35， 45 ℃ were 9.59%， 7.96% and 7.68%， and the relative safe moisture contents were 13.05%， 11.99%， 11.77%， respectively. Mume Flos decoction pieces all contained two water states during the process of hygroscopic absorption at different temperatures， namely bound water T21 and free water T22. During the process of hygroscopic absorption， bound water had the largest increase in peak area. The sum of peak areas of the bound water and free water had a good linear relationship with the moisture contents， and the R2 were 0.959 9， 0.911 8 and 0.974 7 at 25， 35， 45 ℃， respectively. When Aw<0.57， T21 did not change， and the water molecular mobility remained unchanged. When Aw>0.57， T21 showed an increasing trend， and the water molecular mobility increased. The moisture contents of Mume Flos decoction pieces were 8.44%， 6.81% and 6.25% when the water molecular mobility increased at 25， 35， 45 ℃， respectively. ConclusionCombined with the theory of water activity and water molecular mobility， 6.25% is recommended as the safe storage moisture content of Mume Flos decoction pieces， this study can provide reference for determining the safe storage moisture content of other decoction pieces.

Different Head Group Dependence on the Lipid ThermodynamicProperty of the Myelin Basic Protein in the Lipid Monolayer / 中国生物化学与分子生物学报

The 18. 5 kD myelin basic protein (MBP) isoform interacts with phospholipids and its role has been thought to maintain the stability and compactness of the myelin sheath structure. In this study, we describe the statistical thermodynamic theory of certain concentration effects on MBP in the majormyelin lipid (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethano-lamine (POPE), and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine(POPS)) monolayers at the air/ subphase interface via the Langmuir-Blodgett (LB) technique. A simple statistical mechanical theory is established that predicts the interaction between proteins and phosphatehead groups at low surface pressures and the second virial coefficient dependences for the PC, PE, and PS head groups are illustrated. Two-dimensional virial equation of state (2D-VES) suggested that the interaction in the monolayer structure at the MBP-myelin interface is a repulsive force, and it induces a phase change in the monolayer. This is consistent with atomic force microscope (AFM) observations of domain and aggregate structures as well as with changes in the surface morphology induced by MBP. These analyses pertaining to membrane structures will provide a theoretical and experimental basis for the establishment of the myelin membrane modeling system.

Adsorption Properties of Thermally Treated Rice Husk for Removal of Sulfamethazine Antibiotic from Pharmaceutical Wastewater

Equilibrium sorption of the Thermally Treated Rice Husk (TTRH) for Sulfamethazine (SMT) adsorption was studied. The Physico-chemical properties of the modified rice husk were determined. The equilibrium sorption data were fitted into Langmuir, Freundlich and Dubinin–Radushkevich isotherms. Of the three adsorption isotherm, the R2value of Langmuir isotherm model was the highest. Also compared to other isotherms the AARE coefficient for the Langmuir isotherm is low,which indicates favorable sorption. The maximum monolayer coverage (qm) from Langmuir isotherm model was determined to be 19.11 mg/g, the separation factor indicating a favorable sorption experiment is 0.446. Also from Freundlich Isotherm model, the sorption intensity (n) which indicates favorable sorption andthe correlation value are 1.84 and 3.79 respectively. The mean free energy was estimated from Dubinin–Radushkevich isotherm model to be 9.18 KJ/mol which clearly proved that the adsorption experiment followed a physical process

Analysis of Water Adsorption and Thermodynamic Properties of Three Rhei Radix et Rhizoma Decoction Pieces / 中国实验方剂学杂志

Objective:To investigate the moisture adsorption and thermodynamic characteristics of raw products， wine-processed products and fried charcoal products of Rhei Radix et Rhizoma， in order to guide their drying and storage. Method:Static isotherm weighing method was used to determine the adsorption isotherm curves of three Rhei Radix et Rhizoma decoction pieces at 25， 35， 45 ℃， and the test data were fitted with 7 commonly used water adsorption models to determine the best model for studying the adsorption thermodynamic parameters of these decoction pieces. Result:The best adsorption models of these three decoction pieces were all GAB model. At 25， 35， 45 ℃， the absolute safe moisture content of fried charcoal products was 7.43%， 6.79% and 6.20%， of wine-processed products was 8.68%， 8.17% and 7.03%， of raw products was 9.88%， 9.36% and 7.77%， respectively. At 25， 35， 45 ℃， the relative safe moisture content of fried charcoal products was 9.46%， 8.63% and 8.21%， of wine-processed products was 11.49%， 11.03% and 9.74%， of raw products was 13.49%， 12.66% and 11.14%， respectively. The net equivalent heat of adsorption （Qst） and differential entropy （Sd） of these three kinds of decoction pieces all decreased with the increase of equilibrium moisture content， Qst and Sd were in accordance with the entropy-enthalpy complementary theory. The constant velocity temperatures of raw products， wine-processed products and fried charcoal products of Rhei Radix et Rhizoma were 386.66， 391.15， 394.34 K （unit conversion of 1 K=-272.15 ℃）， their Gibbs free energies were 0.372 2， 0.406 0， 0.372 2 kJ·mol-1， respectively. Their adsorption processes were an unspontaneous process driven by enthalpy. Conclusion:The orders of equilibrium moisture content， monomolecular layer moisture content， Qst and Sd of three Rhei Radix et Rhizoma decoction pieces are all raw products>wine-processed products>fried charcoal products. The moisture absorption capacity of the decoction pieces is ranked as raw products>wine-processed products>fried charcoal products. The frying and roasting process significantly affects the hygroscopicity and thermodynamic properties of the three decoction pieces， the reason for this difference may be that the high temperature of the stir-frying results in the decrease of the hygroscopic groups and the increase of the hydrophobic materials in raw products， and the change in the texture of the decoction pieces. The research on the water adsorption characteristics of three Rhei Radix et Rhizoma decoction pieces can provide reference for selecting their storage conditions and drying process.

Contrast effect of biochars and attapulgite clay on the adsorption and removal of cadmium ions from metal contaminated aqueous solution

Aim: To study the contrasting effect of adsorption and removal of cadmium ions using wheat straw biochar, rice straw biochar and attapulgite clay in contaminated aqueous solution. Methodology: Batch sorption experiment was carried out to investigate the parameters influencing the adsorption capacity such as pH, initial cadmium concentration, adsorbent dose and contact time. The physical and chemical characteristics of biochars and clay were studied and adsorption mechanism was analyzed by scanning electron microscopy, infrared spectroscopy, Brunauer-Emmett-Teller and X-ray diffraction, which indicated high adsorption and removal of Cd+2ions by wheat straw biochar was mainly due to the presence of surface carboxyl functional groups –OH, C-O, COOH that reacted Cd2+ions. Results: The adsorption effect of wheat straw biochar (WSB), rice straw biochar (RSB) and attapulgite (ATP) clay were compared. The results showed that adsorption isotherms were best fit to Langmui isotherm model. The adsorption kinetics study well matched with pseudo second order model and the maximum adsorption equilibrium of WSB, RSB and ATP reached to 100, 160, and 120 min, respectively. The results showed that adsorption rate was maximum at pH 6 with 0.1 g dose of adsorbent, 40 mg l-1 metal concentration, and contact time of 100 min at 30°C for WSB. The maximum percent removal of cadmium ions from aqueous solution was in the order WSB>ATP>RSB, 95%, 91% and 88%, respectively. Interpretation: The results explored that wheat straw biochar has high Cd2+adsorption rate and removal efficiency in contaminated water than others. Hence, the results explored that WSB is a potential, low-cost adsorbent and can be used as cadmium decontaminant in polluted water with no secondary pollution.

Adsorción de un complejo de hierro sobre nanocristales de dióxido de titanio utilizando un residuo piridina / Adsorption of an iron complex on nanocrystals of titanium dioxide using a pyridine residue / Adsorção de um complexo de ferro em nanocristais de dióxido de titânio usando um resíduo de piridina

Resumen Debido a que los fenómenos de adsorción de tinturas sobre óxidos metálicos son de gran importancia en la búsqueda de sistemas de conversión de energía solar, en este trabajo se presenta el comportamiento espectroscópico y electroquímico del complejo [Fe(pytpy2)] (PF6)2 (donde pytpy es 4'-(piridin-4-il)-2,2':6',2"-terpiridina) en solución fluida y anclado sobre una película delgada de nanocristales de dióxido de titanio. La constante de formación del aducto se estimó utilizando el modelo isotérmico de Langmuir y se encontró un valor de 1,03x105 M-1 para dicho complejo. El anclaje del complejo sobre la superficie del óxido metálico semiconductor se debe a la interacción del residuo de piridina con los sitios ácidos de Lewis presentes en la superficie del TiO2. Se observó que las propiedades espectroscópicas y electroquímicas del complejo no se ven modificadas por la adsorción.

Abstract Because the phenomena of adsorption of tinctures on metal oxides are of great importance in the search for solar energy conversion systems, this paper presents the spectroscopic and electrochemical behavior of the complex [Fe(pytpy2)](PF6)2 (where pytpy is 4'-(4-pyridyl)-2,2':6',2''-terpyridine) in a fluid solution and anchored on a thin film of nanocrystals of titanium dioxide. The adduct formation constant was estimated using the Langmuir isothermal model, with a value of 1.03x105 M-1 for the complex. The anchoring of the complex on the surface of the semiconductor metal oxide is due to the interaction of the pyridine residue with the Lewis acid sites presented on the TiO2 surface. Results indicated that the spectroscopic and electrochemical properties of the complex are not modified by the adsorption.

Resumo Os fenômenos de adsorção de tinturas em óxidos metálicos são de grande importância na busca por sistemas de conversão de energia solar, motivo pelo qual neste trabalho o comportamento espectroscópico e eletroquímico do complexo [Fe(pytpy2)] (PF6)2 (onde pytpy é 4'-(piridin-4-il)-2,2':6',2"-terpiridina) em uma solução fluida e ancorada em um filme fino de nanocristais de dióxido de titânio. A constante de formação de aduto foi estimada pelo modelo isotérmico de Langmuir, com valor de 1.03x105 M-1 para o referido complexo. A ancoragem do complexo na superfície do óxido de metal semicondutor é devida à interação do resíduo de piridina com os sítios de ácido de Lewis presentes na superfície do TiO2, observando que as propriedades espectroscópicas e eletroquímicas do complexo não são modificadas pela adsorção.

Application of affinity chromatography and its mathematical model in study of active components of traditional Chinese medicine / 中国中药杂志

Affinity chromatography is characterized by its high specificity,high recovery rate and sensitivity,and it has been widely used in the selection of active ingredients of traditional Chinese medicine,separation and enrichment of low molecular weight sugars and protein peptides,research on mechanism of action and discovery of targets.This paper reviewed the application of affinity chromatography and its adsorption isotherm model,kinetic model and adsorption thermodynamic mechanism in the field of traditional Chinese medicine.This summarizes and provides thinking for comprehensive applications of affinity chromatography theory in the field of active ingredient screening,purification and medicine interaction.

Adsorption and availability of phosphorus in response to humic acid rates in soils limed with CaCO3 or MgCO3 / Adsorção e disponibilidade de fósforo em resposta a doses de ácido húmico em solos corrigidos por CaCO3 ou MgCO3

ABSTRACT Humic acid (HA) may reduce adsorption and increase soil P availability, however, the magnitude of this effect is different when Ca2+ prevails over Mg2+ in limed soils. The objective of this study was to evaluate the effects of HA rates and carbonate sources on the adsorption, phosphate maximum buffering capacity (PMBC), and P availability in two contrasting soils. Oxisol and Entisol samples were firstly incubated with the following HA rates: 0, 20, 50, 100, 200 and 400 mg kg-1, combined with CaCO3 or MgCO3, to evaluate P adsorption. In sequence, soil samples were newly incubated with P (400 mg kg-1) to evaluate P availability. The least P adsorption was found when 296 mg kg-1 of HA was added to Oxisol. Applying HA rates decreased maximum adsorption capacity, increased P binding energy to soil colloids and did not alter PMBC of Entisol. Available P contents in Oxisol increased with HA rates, but it did not change in Entisol. Choosing the right HA rate can decrease PMBC up to 40% and increase the Oxisol P availability by 17%. Application of MgCO3 instead of CaCO3 decreased P adsorption in both soils. Thus, a positive correlation between Ca2+ content and PMBC was verified. Optimum rate of HA and the preponderance of Mg2+ instead of Ca2+ in soil volume fertilized with P are effective practices to reduce adsorption and increase P availability, especially in clayey Oxisol.

RESUMO O ácido húmico (AH) pode reduzir a adsorção e aumentar a disponibilidade de P nos solos, entretanto, a magnitude desse efeito é diferente quando o Ca2+ prevalece sobre Mg2+ em solos com acidez corrigida. Objetivou-se avaliar os efeitos de doses de AH e fontes de carbonato na adsorção, fator capacidade de P máximo (FCPm) e disponibilidade de P em solos contrastantes. Amostras de Latossolo e Gleissolo foram primeiramente incubadas com as seguintes doses de AH: 0, 20, 50, 100, 200 e 400 mg kg-1, combinadas com CaCO3 ou MgCO3, para avaliar a adsorção de P. Em sequência, as amostras de solo foram novamente incubadas com P (400 mg kg-1), para determinar a disponibilidade de P. A aplicação de doses de AH reduziu a capacidade máxima de adsorção, aumentou a energia de ligação do P e não alterou a FCPm do Gleissolo. O teor de P disponível aumentou com o acréscimo das doses de AH no Latossolo, contudo, não foram alterados no Gleissolo. A escolha correta da dose de AH reduziu a FCPm em até 40% e aumentou a disponibilidade de P no Latossolo em 17%. A aplicação de MgCO3 em vez do CaCO3 reduziu a adsorção de P em ambos os solos. Assim, houve correlação positiva entre o teor de Ca2+ e a FCPm. A dose ótima de AH e a predominância de Mg2+ sobre Ca2+ no volume de solo adubado com P são práticas efetivas para reduzir a adsorção e aumentar a disponibilidade de P, especialmente, no Latossolo argiloso.

Kinetic and Isotherm of Mn(II) Biosorption by Lyophilized Cells of Proteus penneri 2120 (KY712431) Isolated from Industrial Wastewater

This study aimed to isolate and identify a novel bacterial isolate potential resistant to Mn2+ as well as to investigate the biosorption isotherms of Mn2+ removal from aqueous solutions by the freeze-dried biomass of this bacterium. Sixty three manganese resistant bacterial isolates were recovered from 20 industrial wastewater samples. Interestingly, among them, the isolate number 2120 was able to resist up to 140 ppm of Mn2+ and was selected for the further processes. This isolate was phenotypically characterized and identified by 16S rRNA gene sequencing as Proteus penneri and assigned accession number KY712431 in the GenBank database. The effects of pH and contact time on the biosorption process were studied and optimum pH for biosorption equilibrium was 6 while the optimum contact time was 30 min at room temperature. The maximum adsorption capacity (qmax) of Mn2+ removal from aqueous solutions by the freeze-dried biomass of Proteus penneri 2120 was 175.4 mg/g. According to Freundlich and Langmuir models, the correlation coefficients (R2) were 0.9977 and 0.5525, respectively. Therefore the studied biosorption isotherms are fit well with Freundlich model rather than the Langmuir model. Our findings suggest that the dried biomass of the isolate Proteus penneri 2120 is potentially applicable for manganese metal ion removal from the industrial waste water.

Adsorption Isotherm and Thermodynamic Profile of Hexavalent Chromium onto Lumbang (Aleurites moluccana) Activated Carbon Chitosan Composite Crosslinked with Epichlorohydrin

Adsorption isotherm and thermodynamic profile of hexavalent chromium onto lumbang (Aleurites moluccana) activated carbon chitosan composite crosslinked with epichlorohydrin were studied. The optimum conditions were identified at pH 3, contact time of 75 min, adsorbent dose of 3 g/L, initial concentration of 60 ppm, and 30ºC temperature resulted to a removal efficiency of 93%. The composite has a round and elliptical adsorption sites, contains –OH and –NH2 functional groups, and has increased stability with epichlorohydrin crosslinking. The adsorption process is best characterized by the Langmuir isotherm suggesting a monolayer adsorption nature of Cr(VI). The adsorption kinetics obeyed the pseudo-second order model and the adsorption process is exothermic. The investigated adsorption phenomenon described a chemisorption process, with 21.32 kJ mol-1 mean free energy, due to the functional groups identified and the high porosity of the adsorbent surfaces.

Capacidad de adsorción de plomo con intercambiadores catiónicos de carbón xantado / Adsorption capacity of lead with cationics exchangers of xanted coal

En este estudio, se describe la adsorción de plomo (Pb2+) en soluciones acuosas, a partir de carbón modificado, mediante tratamiento con CS2 y NaOH, empleando una relación 16,6:1 NaOH/Carbón p/p y 4,08:1 CS2/carbón p/p. Se realizaron pruebas de pH, cinéticas e isotermas de adsorción, para evaluar la capacidad de adsorción del carbón xantado y carbón no xantado. Los grupos azufre en el carbón xantado fueron identificados por espectroscopia infrarroja de reflectancia difusa (FTIR) y comparados con los espectros del carbón no xantado. Los resultados muestran que la mejor remoción de plomo en la solución con una concentración de 100mg de Pb2+/L y dosis de 50mg de adsorbente/10mL, respectivamente, fue a un valor de pH 5,0, logrando un porcentaje de adsorción de 98%. Los estudios cinéticos indican que el proceso de adsorción puede alcanzar el equilibrio alrededor de 120min, siguiendo una cinética de pseudo-segundo orden, para ambos materiales. El estudio de las isotermas indica que el carbón se ajusta mejor a una isoterma de tipo Langmuir y cuando se somete a la xantación, se ajusta a una isoterma de tipo Freundlich.

This study describes the adsorption of lead (Pb2+) in aqueous solutions of modified coal by treatment with CS2 and NaOH, using a ratio of 16,6:1 NaOH/coal (w/w) and 4,08 CS2/coal (w/w). Different tests such as acidity, kinetic and adsorption isotherms were carried out in order to assess the adsorption capacity of xanted and non-xanted coal. The sulfur groups presented in the xanted coal were identified by infrared spectroscopy(FTIR) and they were compared with non-xanted coal spectrum. The results show that the best lead removal in the solution (with a concentration of 100mg Pb2+/L and 50mg of adsorbent) was obtained at pH 5.0 for both coal (xanted and non-xanted) with an adsorption percentage of 98%. The kinetic studies indicate that the adsorption process can reach the equilibrium in about 120 minutes, following a pseudo-second order kinetics for both materials. The isotherms study indicates that the coal fits best to a Langmuir-type isotherm, however when the coal is xanted, it fits best to a Freundlich-type isotherm.

Panus tigrinus as a potential biomass source for Reactive Blue decolorization: isotherm and kinetic study

Background: Textile and dye industries pose a serious threat to the environment. Conventional methods used for dye treatment are generally not always effective and environmentally friendly. This drove attention of scores of researchers to investigate alternative methods for the biodegradation of dyes using fungal strains. In this work, white-rot fungus (Panus tigrinus) was used as a biosorbent for the decolorization of Reactive Blue 19. The process parameters that were varied were initial concentration (50­150 mg/L), contact time (30­90 min), and pH (2­6). In addition, to gain important data for the evaluation of a sorption process, the equilibrium and kinetics of the process were determined. Results: White-rot fungus showed great potential in decolorizing Azo dyes. The strain showed the maximum decolorization of 83.18% at pH 2, a contact time of 90 min, and an initial concentration of 50 mg/L. The Langmuir isotherm described the uptake of the Reactive Blue 19 dye better than the Freundlich isotherm. Analysis of the kinetic data showed that the dye uptake process followed the pseudo second-order rate expression. Conclusion: The biosorption process provided vital information on the process parameters required to obtain the optimum level of dye removal. The isotherm study indicated the homogeneous distribution of active sites on the biomass surface, and the kinetic study suggested that chemisorption is the rate-limiting step that controlled the biosorption process. According to the obtained results, P. tigrinus biomass can be used effectively to decolorize textile dyes and tackle the pollution problems in the environment.

Modelling the effect of temperature on the water sorption isotherms of chitosan films

Abstract The interaction of the water molecules from the environment with foods and other materials can be evaluated using sorption isotherms. Films and biodegradable films are susceptible to changes in their functional characteristics due to adsorbed water. The amount of moisture that biodegradable films can adsorb depends on the temperature, relative humidity of the storage area and chemical composition. Several mathematical models can be used to describe the behavior of sorption isotherms in biodegradable films and some of them have been modified to include the temperature parameter into the equation. In this research, the original and modified BET, GAB, Halsey, Henderson and Oswin models were assessed to determine their suitability describing the behavior of moisture adsorption isotherms of chitosan films at 15, 20, 25 and 30 °C. The modified models of GAB, Oswin and Halsey gave the best fit to the experimental sorption data of the chitosan films, with R2 values higher than 0.97 demonstrating that those models describe better the sorption isotherms at the temperatures studied.

Investigation on crystal structure and moisture sorption properties of riboflavin / 中国药学杂志

OBJECTIVE: To establish the detection technology of riboflavin polymorphism, and investigate the moisture sorption properties of riboflavin. METHODS: The two crystal forms of riboflavin were characterized by different analysis methods, such as powder X-ray diffraction method (p-XRD), differential scanning calorimetry method (DSC) and infrared spectrum method (IR). Dynamic vapor sorption (DVS) analysis was adopted to acquire moisture sorption dynamics of the two crystal forms. The influences of temperature, humidity and light on crystal transformation were explored. RESULTS: The crystal forms of two batches of riboflavin samples were identified as anhydrate I and monohydrate, respectively. The monohydrate could be obtained by recrystallizing in DM-SO. The monohydrate was hygroscopic, the number of crystal water may change at different relative humidities, and the moisture sorption dynamics of the monohydrate was greatly influenced by temperature. The anhydrate I was almost non-hygroscopic, and temperature hardly affected its moisture sorption dynamics. CONCLUSION: Characteristic data for riboflavin polymorphism are obtained, and the results show that anhydrate I is more stable than monohydrate. This study indicates that DVS could be used in studies on drug polymorphism.

Moisture sorption properties research of chemical reference substances based on dynamic vapor sorption analysis technology / 中国药学杂志

OBJECTIVE: To investigate the moisture sorption properties of chemical reference substances (CRSs) by using dynamic vapor sorption (DVS) analysis technology in order to establish the distribution conditions, packaging materials, and usages of national chemical reference substances. METHODS: DVS analysis was adopted to acquire the moisture sorption dynamic profiles of five chemical reference substances of different moisture sorption types to evaluate their moisture sorption trend and capacities under different humidities. RESULTS: According to moisture sorption dynamics, we can found the hygroscopicity of disodium etidronate, sodium aminosalicylate, valaciclovir hydrochloride, aspirin and bosentan, and we have given advices about how to use these CRSs and what kind of bottles they should be packed in. CONCLUSION: DVS analysis can be used to record moisture sorption data in real time and visually observe water-CRS interactions under different humidities, which is an important technology for guiding the establishment and distribution of CRSs.

Partial Purification of Cellulase Enzyme from Fusarioum oxysporium by Using Egg White Matrix.

Aim: Protein matrix possesses a capacity to bind organic and inorganic matter. Egg white matrix as an adsorbent was utilized for partial purification of cellulase enzyme in detailed batch study. Methodology: Effect of pH, matrix size, enzyme concentration, contact time and temperature on the binding of cellulase on egg white matrix was studied. Desorption studies was carried with variable pH, sodium chloride and ammonium sulphate system to desorbs the cellulase for the egg white matrix. Results: Equilibrium isotherms for the adsorption of the cellulase enzyme on egg white matrix were well fitted to Freundlich and Langmuir isotherm models. The adsorption process has been found endothermic in nature and thermodynamic parameters, Gibb’s free energy (ΔGº), change in enthalpy (ΔHº) and change in entropy (ΔSº) have been calculated as -13276.21, 2025.47 and 698.64 (KJ mol-1) respectively. Thermodynamic studies revealed that the adsorption process is spontaneous and endothermic in nature. In desorption studies it was concluded that maximum elution (66.8% was obtained for cellulase enzyme with 0.3M (NH4)2SO4 with respect to different pH and sodium chloride solution. Cellulase enzyme obtained after desorption process has maximum purification fold of 4.25 with 60% recovery. Conclusion: The results from the current research suggest that egg white can be used for partial purification of cellulase enzyme with less cost.

Low cost single-step purification of endoglucanase from Aspergillus fumigatus ABK-9.

Low cost agro-waste was used as adsorption support for single-step purification of endoglucanase from the culture filtrate of A. fumigatus ABK-9. Among various agro-waste substrates, 1% NaOH pretreated rice bran was proved to be the best for adsorbing about 74.8 and 71.1% of endoglucanase at 4 °C and 10 °C respectively. Langmuir type adsorption isotherm at 4 °C showed maximum adsorption of enzyme at pH 5.0, which was in the range of optimum pH of the enzyme. The rice bran column bound enzyme was maximally eluted by a mixture of acetate buffer (0.05 M, pH 5.5) and ethanol (40%, v/v) at a ratio of 3:2 and a flow rate of 1 mL/min. A 5.52-fold purification of the enzyme was achieved from culture supernatant. The specific activity and recovery yield after purification were 294.0 U/mg and 40.15%, respectively, which were comparable with other contemporary protocols. The homogeneity of the enzyme was tested through sodium dodecyl sulphate polyacrylamide gel electrophoresis and a single band of 56.3 kDa was observed. Zymogram analysis finally confirmed the occurrence of endoglucanase in the single band.

Sorção e mobilidade do lítio em solos de áreas de disposição final de resíduos sólidos urbanos / Sorption and mobility of lithium in soil areas of final disposition of municipal solid waste

Um dos grandes problemas da atualidade é a disposição inadequada dos resíduos sólidos urbanos no solo, e seus efeitos recaem, principalmente, na contaminação das águas e do solo. Este trabalho objetivou o estudo da sorção e da mobilidade do Lítio nos solos das áreas de disposição de resíduos sólidos urbanos dos municípios de Lavras, Campo Belo e Pouso Alegre, MG. A partir dos ensaios de sorção em batelada e mobilidade do Li em colunas de solo, ajustaram-se os parâmetros das isotermas de Freundlich e da equação de transporte de solutos no solo. Pelos resultados obtidos verificou-se que, dentre os solos avaliados, o do município de Lavras foi o que apresentou a maior mobilidade do Li seguido dos solos de Pouso Alegre e Campo Belo, sendo, portanto, mais vulnerável à contaminação das águas subterrâneas.

A major problem today is the improper disposal of solid waste in the soil, and its effects fall mainly in the contamination of water and soil. This work aimed to study the sorption and mobility of lithium in soil disposal areas of solid waste from Lavras, Campo Belo and Pouso Alegre, Brazil. From the batch sorption tests and Li mobility in soil columns, set up the parameters of the Freundlich isotherms and the equation of solute transport in soil. The results obtained showed that, among the soils evaluated, the city of Lavras showed the increased mobility of Li followed by Pouso Alegre and Campo Belo soils, and are therefore more vulnerable to groundwater contamination.

Study on Thermodynamics and Adsorption kinetics of Purified endoglucanase (CMCase) from Penicillium notatum NCIM NO-923 produced under mixed solid-state fermentation of waste cabbage and Bagasse

In the current study, one thermostable endoglucanase was purified from Penicillium notatum NCIM NO-923 through mixed solid state fermentation of waste cabbage and bagasse. The molecular weight of the purified enzyme was 55kDa as determined by SDS polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme had low activation energy (Ea) of 36.39KJ mol-1 for carboxymethyl cellulose hydrolysis and the enthalpy and entropy for irreversible inactivation was 87 kJ mol −1 and 59.3 J mol −1 K−1 respectively. The enzyme was quite thermostable with a Tm value of 62.2˚C. The pKa1 and pKa2 of ionizable groups of the active sites were 2.5 and 5.3 respectively. Apparent Km, Vmax and Kcat of the enzyme were found to be 5.2 mg mL-1, 80 U/gds and 322.4 sec-1 respectively. The enzyme showed about 1.4 fold increased activity in presence of 10mM MgSO4. Adsorption of endoglucanase on Avicel at wide pH range was studied at different temperatures. Langmuir type adsorption isotherm at 10˚C showed maximum adsorption strength of enzyme at pH 3.0, which was in a range of optimum pH of the enzyme.