Biomass accumulation and energy conversion efficiency in aromatic rice genotypes

A field experiment was conducted to evaluate photosynthetic efficiency along with different growth parameters of aromatic rice genotypes. Forty genotypes including three non-aromatic checks exhibited enormous variations for leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), grain yield, total dry matter, harvest index and photosynthetic efficiency or energy use efficiency (Eμ) at panicle initiation and heading stages. Minimum LAI-value was 0.52 in Khazar at PI stage and maximum was 4.91 in Sakkor khora at heading stage. The CGR-value was in the range of 4.80−24.11 g m⁻² per day. The best yielder BR39 produced grain of 4.21 t ha⁻¹ and the worst yielder Khazar gave 1.42 t ha⁻¹. Total dry matter (TDM) yield varied from 4.04 to 12.26 t ha⁻¹ where genotypes proved their energy use efficiency a range between 0.58 to 1.65%. Eμ showed a significant positive relation with TDM (r = 0.80^**), CGR (r = 0.72^**) and grain yield (r = 0.66^**). A negative correlation was established between TDM and harvest index and LAI and RGR. Path analysis result showed that NAR at heading stage exerted highest positive direct effect (0.70) on Eμ.     

Productivity, carbon dioxide uptake and net energy return of microalgal bubble column photobioreactors

This work examined the energy return of Chlorella vulgaris and Dunaliella tertiolecta cultivated in a gas-sparged photobioreactor design where the power input for sparging was manipulated (10, 20, and 50 W m⁻³). Dry weight, organic carbon and heating values of the biomass were measured, plus a suite of variables including Fv/Fm and dissolved oxygen. A model for predicting the higher heating value of microalgal biomass was developed and used to measure the energetic performance of batch cultivations. High power inputs enhanced maximum biomass yields, but did not improve the energy return. Cultivation in 10 W m⁻³ showed up to a 39% higher cumulative net energy return than 50 W m⁻³, and increased the cumulative net energy ratio up to fourfold. The highest net energy ratio for power input was 19.3 (D. tertiolecta, 12% CO₂, 10 W m⁻³). These systems may be a sustainable method of biomass production, but their effectiveness is sensitive to operational parameters.     

Influence of sward maturity and pre-conditioning temperature on the energy production from grass silage through the integrated generation of solid fuel and biogas from biomass (IFBB): 1. The fate of mineral compounds

The IFBB process, which separates biomass into a press fluid for biogas production and a press cake for combustion, is aimed at converting low-input high-diversity grasslands into energy, which is problematic with conventional conversion techniques. Herbage from a lowland hay meadow (Arrhenaterion) was sampled on eight dates between 24 April and 21 June 2007. Silage from each date was processed in six treatments without and with hydrothermal conditioning at different temperatures. The impact on mass flows of plant compounds and on elemental concentrations in the press cake was investigated. Elements detrimental for combustion were significantly reduced in the press cake compared to the silage. Mass flows and elemental concentrations in the press cake were strongly influenced by conditioning temperature as well as concentration of neutral detergent fiber and dry matter in the silage (R² from 0.70 to 0.99). Press cakes of late sampling dates were considered best suitable for combustion.     

Treatment of industrial wastewater with two-stage constructed wetlands planted with Typha latifolia and Phragmites australis

Industrial wastewater treatment comprises several processes to fulfill the discharge permits or to enable the reuse of wastewater. For tannery wastewater, constructed wetlands (CWs) may be an interesting treatment option. Two-stage series of horizontal subsurface flow CWs with Phragmites australis (UP series) and Typha latifolia (UT series) provided high removal of organics from tannery wastewater, up to 88% of biochemical oxygen demand (BOD₅) (from an inlet of 420 to 1000 mg L⁻¹) and 92% of chemical oxygen demand (COD) (from an inlet of 808 to 2449 mg L⁻¹), and of other contaminants, such as nitrogen, operating at hydraulic retention times of 2, 5 and 7 days. No significant (P < 0.05) differences in performance were found between both the series. Overall mass removals of up to 1294 kg COD ha⁻¹ d⁻¹ and 529 kg BOD₅ ha⁻¹ d⁻¹ were achieved for a loading ranging from 242 to 1925 kg COD ha⁻¹ d⁻¹ and from 126 to 900 kg BOD₅ ha⁻¹ d⁻¹. Plants were resilient to the conditions imposed, however P. australis exceeded T. latifolia in terms of propagation.     

Long-term effects on the nitrogen budget of a short-rotation grey alder (Alnus incana (L.) Moench) forest on abandoned agricultural land

Short-rotation energy forestry is one of the potential ways for management of abandoned agricultural areas. It helps sequestrate carbon and mitigate human-induced climate changes. Owing to symbiotic dinitrogen (N₂) fixation by actinomycetes and the soil fertilizing capacity and fast biomass growth of grey alders, the latter can be suitable species for short-rotation forestry. In our study of a young grey alder stand (Alnus incana (L.) Moench) on abandoned arable land in Estonia we tested the following hypotheses: (1) afforestation of abandoned agricultural land by grey alder significantly affects the soil nitrogen (N) status already during the first rotation period; (2) input of symbiotic fixation covers an essential part of the plant annual N demand of the stand; (3) despite a considerable N input into the ecosystem of a young alder stand, there will occur no significant environmental hazards (N leaching or N₂O emissions). The first two hypotheses can be accepted: there was a significant increase in N and C content in the topsoil (from 0.11 to 0.14%, and from 1.4 to 1.7%, respectively), and N fixation (151.5 kg N ha⁻¹ yr⁻¹) covered about 74% of the annual N demand of the stand. The third hypothesis met support as well: N₂O emissions (0.5 kg N ha⁻¹ yr⁻¹) were low, while most of the annual gaseous N losses were in the form of N₂ (73.8 kg N ha⁻¹ yr⁻¹). Annual average NO₃-N leaching was 15 kg N ha⁻¹ yr⁻¹ but the N that leached from topsoil accumulated in deeper soil layers. The soil acidifying effect of alders was clearly evident; during the 14-year period soil acidity increased 1.3 units in the upper 0-10 cm topsoil layer.     

Comparison of polysialic acid production in Escherichia coli K1 during batch cultivation and fed-batch cultivation applying two different control strategies

The polysialic acid (PSA) production in Escherichia coli (E. coli) K1 was studied using three different cultivation strategies. A batch cultivation, a fed-batch cultivation at a constant specific growth rate of 0.25 h⁻¹ and a fed-batch cultivation at a constant glucose concentration of 50 mg l⁻¹ was performed. PSA formation kinetics under different cultivation strategies were analyzed based on the Monod growth model and the Luedeking-Piret equation. The results revealed that PSA formation in E. coli K1 was completely growth associated, the highest specific PSA formation rate (0.0489 g g⁻¹ h⁻¹) was obtained in the batch cultivation. However, comparing biomass and PSA yields on the glucose consumed, both fed-batch cultivations provided higher yields than that of the batch cultivation and acetate formation was prevented. Moreover, PSA yield on glucose was also correlated to the specific growth rate of the cells. The optimal specific growth rate for PSA production was 0.32 h⁻¹ obtained in the fed-batch cultivation at a constant glucose concentration of 50 mg l⁻¹, with highest conversion efficiency of 43 mg g⁻¹.     

Primary production,respiration and calcification of the temperate free-living coralline alga Lithothamnion corallioides

Calcification and primary production responses to irradiance in the temperate coralline alga Lithothamnion corallioides were measured in summer 2004 and winter 2005 in the Bay of Brest. Coralline algae were incubated in dark and clear bottles exposed to different irradiances. Net primary production reached 1.5 μmol C g⁻¹ dry wt h⁻¹ in August and was twice as high as in January–February. Dark respiration showed significant seasonal variations, being three-fold higher in summer. Maximum calcification varied from 0.6 μmol g⁻¹ dry wt h⁻¹ in summer 2004 to 0.4 μmol g⁻¹ dry wt h⁻¹ in winter 2005. According to P–E curves and the daily course of irradiance, estimated daily net production and calcification reached 131 μg C g⁻¹ dry wt and 970 μg CaCO₃ g⁻¹ dry wt in summer 2004, and 36 μg C g⁻¹ dry wt and 336 μg CaCO₃ g⁻¹ dry wt in winter 2005. The net primary production of natural L. corallioides populations in shallow waters was estimated at 10–600 g C m⁻² y⁻¹, depending on depth and algal biomass. The mean annual calcification of L. corallioides populations varied from 300 to 3000 g CaCO₃ m⁻². These results are similar to those reported for tropical coralline algae in terms of carbon and carbonate productivity. Therefore, L. corallioides can be considered as a key element of carbon and carbonate cycles in the shallow coastal waters where they live.     

Prey selection by the common dolphin: Fulfilling high energy requirements with high quality food

Which characteristics define the prey species constituting the diet of a given predator? Answering this question would help predict a predator's diet and improve our understanding of how an ecosystem functions. The aim of this study was to test if the diet of common dolphins, Delphinus delphis, in the oceanic Bay of Biscay reflected prey availability or a selection shaped by prey energy densities (ED). To do this, the community of potential prey species, described both in terms of relative abundance and energy densities, was compared to the common dolphin diet in this area. This analysis of a predator's diet and its prey field revealed that the common dolphin selected its diet on the basis of prey energy densities (significant values of Chesson's index for ED > 5 kJ g^− 1). High-energy prey were positively selected in the diet [e.g. Notoscopelus kroeyeri, ED = 7.9 kJ g^− 1, 9% of relative abundance in the environment (%Ne); 62% of relative abundance in the diet (%Nd)] and low-energy prey disregarded (Xenodermichthys copei, ED = 2.1 kJ g⁻¹, 20%Ne, 0%Nd). These results supported the hypothesis that common dolphins selected high energy density prey species to meet their energetically expensive life style and disregard prey organisms of poor energy content even when abundant in the environment.     

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition

Two techniques are described to calculate energy densities for the bell, gonad and oral arm tissues of three scyphozoan jellyfish (Cyanea capillata, Rhizostoma octopus and Chrysaora hysoscella). First, bomb-calorimetry was used, a technique that is readily available and inexpensive. However, the reliability of this technique for gelatinous material is contentious. Second, further analysis involving the more labour intensive proximate-composition analysis (protein, fat and carbohydrate) was carried out on two species (C. capillata and R. octopus). These proximate data were subsequently converted to energy densities. The two techniques (bomb-calorimetry and proximate-composition) gave very similar estimates of energy density. Differences in energy density were found both amongst different species and between different tissues of the same species. Mean (± S.D.) energy density estimates for whole animals from bomb-calorimetry were 0.18 ± 0.05, 0.11 ± 0.04, and 0.10 ± 0.03 kJ g wet mass^− 1 for C. capillata, R. octopus, and C. hysoscella respectively. The implications of these low energy densities for species feeding on jellyfish are discussed.     

Physiological and morphological effects of long-term ammonium or nitrate deposition on the green and red (shade and open grown) Sphagnum capillifolium

Sphagna are vulnerable to enhanced nitrogen (N) deposition. This article reports how the green (shade, under Calluna) and red (open grown) Sphagnum capillifolium respond to ammonium and nitrate additions of 56 kg N ha⁻¹ y⁻¹ over the background of 8-10 kg N ha⁻¹ y⁻¹ on an ombrotrophic bog in the Scottish Borders after seven years. Samples and measurements were made during a range of hydrated and desiccated conditions in the summer of 2009. Both ammonium and nitrate increased moss N concentration, but while ammonium decreased cross-sectional area of leaf hyaline cells and the leaf hyaline/chlorophyllose cell area ratio, nitrate increased both of them and capitulum pH. The changes in leaf morphology have not previously been reported to our knowledge. Especially the red S. capillifolium was affected by ammonium with significant changes in shoot N concentration (+71%) and the cross-sectional area of leaf chlorophyllose cells (+67%), and reductions in shoot dry weight (−30%) and fresh weight (−42%), the cross-sectional area of leaf hyaline cells (−24%), the leaf hyaline/chlorophyllose cell area ratio (−54%), as well as in chlorophyll fluorescence (measured as F_v/F_m) of desiccated capitulum (−65%) (all p < 0.05). These observations show that N deposition may affect moss physiology also through changes in leaf anatomy and morphology. The results also highlight potential sampling issues and causes of variability in N responses when collecting variably pigmented Sphagna.     

Laboratory experiments on the effects of variable suspended sediment concentrations on the ecophysiology of the porcelain crab Petrolisthes elongatus (Milne Edwards, 1837)

The porcelain crab Petrolisthes elongatus is a particulate suspension feeding species common to coastal areas of New Zealand (NZ). Consistent with the responses of other suspension feeding species, it is likely to be negatively influenced by elevated suspended sediment concentrations. Laboratory experiments were conducted to quantify the effect of temperature (12 °C, 15 °C and 18 °C) and suspended sediment concentration (total particulate matter (TPM): low < 100 mg L^− 1; medium 100-1000 mg L^− 1; high > 1000 mg L^− 1) on the clearance rate (CR in L h^− 1), oxygen uptake rate (VO₂ in mL h⁻¹), net absorption efficiency (AE), and net energy budget (NEB in J h^− 1) of P. elongatus across a range of sizes. Variation in CR and AE was independent of temperature and of body size, but were significantly different (P < 0.05) at low and medium suspended sediment concentrations compared with high suspended sediment concentrations. CR responded in a non-linear manner to changes in TPM, increasing with TPM up to a maximum value at medium-low concentrations (approximately 250 mg L^− 1) and then decreasing thereafter. CR had almost completely shut down at TPM concentrations of > 1000 mg L^− 1 and at particulate organic matter (POM) concentrations of > 250 mg L^− 1. AE was zero at approximate TPM and POM values of 1200 mg L^− 1 and 300 mg L^− 1, respectively. VO₂ was positively correlated with body size and with temperature, but was independent of TPM. NEB values for P. elongatus were low (approx 110 J g^− 1 h^− 1) at low sediment concentrations, were high (approx 320 J g^− 1 h^− 1) at medium sediment concentrations, and were negative (approx − 114 J g^− 1 h^− 1) at high sediment concentrations. These findings indicate that P. elongatus is likely to be food-limited at sediment concentrations of < 100 mg L^− 1, and severely negatively affected at sediment concentrations of > 1000 mg L^− 1, at least for the duration of such events which may persist for 2-3 days in coastal environments where this crab occurs.     

The role of phase separation and feed cycle length in leach beds coupled to methanogenic reactors for digestion of a solid substrate (Part 1): Optimisation of reactors' performance

A two-phase system composed by a leach bed and a methanogenic reactor was modified for the first time to improve volumetric substrate degradation and methane yields from a complex substrate (maize; Zeamays). The system, which was operated for consecutive feed cycles of different durations for 120 days, was highly flexible and its performance improved by altering operational conditions. Daily substrate degradation was higher the shorter the feed cycle, reaching 8.5 g TS_destroyed d⁻¹ (7-day feed cycle) but the overall substrate degradation was higher by up to 55% when longer feed cycles (14 and 28 days) were applied. The same occurred with volumetric methane yields, reaching 0.839 m³ (m³)⁻¹ d⁻¹. The system performed better than others on specific methane yields, reaching 0.434 m³ kg⁻¹ TS_added, in the 14-day and 28-day systems. The UASB and AF designs performed similarly as second stage reactors on methane yields, SCOD and VFA removal efficiencies.     

An unusual thermostable aspartic protease from the latex of Ficus racemosa (L.)

The most extensively studied ficins have been isolated from the latex of Ficus glabrata and Ficus carica. However the proteases (ficins) from other species are less known. The purification and characterization of a protease from the latex of Ficus racemosa is reported. The enzyme purified to homogeneity is a single polypeptide chain of molecular weight of 44,500 ± 500 Da as determined by MALDI-TOF. The enzyme exhibited a broad spectrum of pH optima between pH 4.5-6.5 and showed maximum activity at 60 ± 0.5 °C. The enzyme activity was completely inhibited by pepstatin-A indicating that the purified enzyme is an aspartic protease. Far-UV circular dichroic spectra revealed that the purified enzyme contains predominantly β-structures. The purified protease is thermostable. The apparent T_m, (mid point of thermal inactivation) was found to be 70 ± 0.5 °C. Thermal inactivation was found to follow first order kinetics at pH 5.5. Activation energy (E_a) was found to be 44.0 ± 0.3 kcal mol⁻¹. The activation enthalpy (ΔH^∗), free energy change (ΔG^∗) and entropy (ΔS^∗) were estimated to be 43 ± 4 kcal mol⁻¹, −26 ± 3 kcal mol⁻¹ and 204 ± 10 cal mol⁻¹ K⁻¹, respectively. Its enzymatic specificity studied using oxidized B chain of insulin indicates that the protease preferably hydrolyzed peptide bonds C-terminal to glutamate, leucine and phenylalanine (at P₁ position). The broad specificity, pH optima and elevated thermal stability indicate the protease is distinct from other known ficins and would find applications in many sectors for its unique properties.     

Solid Fuel Generation from Urban Leaf Litter in Mixture with Grass Cuttings: Chemical Composition,Energetic Characteristics,and Impact of Preprocessing

Urban biomass from green areas is a potential resource for bioenergy recovery, which is widely unused. Different types of organic material (e.g., grass, leaf litter) usually occur in mixtures due to common collecting practice. Forty samples of grass, leaf litter (genera: Acer, Quercus, Tilia), and mixtures of both, containing one third grass or leaf litter, were investigated to evaluate the effect of the “Integrated Generation of Solid Fuel and Biogas from Biomass” (IFBB) on material and energy fluxes as well as relevant characteristics of resulting energy carriers. IFBB divides biomass into a fiber-rich press cake and a highly digestible press fluid by mashing with subsequent pressing. Ensiling of samples was successful with pH values ranging from 4.2 in grass to 4.8 in pure Tilia samples. Concentration of most minerals with exception of Ca and Mg were higher in grass than in leaf litter silage. The IFBB treatment reduced the element concentration in the press cake independently from the substrate. Linear regression models revealed high influence of the initial concentration in silage on the concentration in the press cake. The lower heating value of the press cake was nearly constant (19 MJ kg^?1 DM_{ash free}) independent from mixture. Methane yields from press fluid digestion ranged from 172 (mean of leaf litter samples) to 325 l_N?kg^?1 VS (mixture of 33 % leaf litter—66 % grass). For an evaluation of the economic and ecological potential, models of the spatial and temporal occurrence of these biomasses need to be established.     

Ethanol production from syngas by Clostridium strain P11 using corn steep liquor as a nutrient replacement to yeast extract

The feasibility of replacing yeast extract (YE) by corn steep liquor (CSL), a low cost nutrient source, for syngas fermentation to produce ethanol using Clostridium strain P11 was investigated. About 32% more ethanol (1.7 g L⁻¹) was produced with 20 g L⁻¹ CSL media in 250-mL bottle fermentations compared to media with 1 g L⁻¹ YE after 360 h. Maximum ethanol concentrations after 360 h of fermentation in a 7.5-L fermentor with 10 and 20 g L⁻¹ CSL media were 8.6 and 9.6 g L⁻¹, respectively, which represent 57% and 60% of the theoretical ethanol yields from CO. Only about 6.1 g L⁻¹ of ethanol was obtained in the medium with 1 g L⁻¹ YE after 360 h, which represents 53% of the theoretical ethanol yield from CO. The use of CSL also enhanced butanol production by sevenfold compared to YE in bottle fermentations. These results demonstrate that CSL can replace YE as the primary medium component and significantly enhance ethanol production by Clostridium strain P11.     

Electricity generation in single-chamber microbial fuel cells using a carbon source sampled from anaerobic reactors utilizing grass silage

Production of electricity from samples obtained during anaerobic digestion of grass silage was examined using single-chamber air-cathode mediator-less microbial fuel cells (MFCs). The samples were obtained from anaerobic reactors at start-up conditions after 3 and 10 days of operation under psychrophilic (15 °C) and mesophilic (37 °C) temperatures. Electricity was directly produced from all samples at a concentration of 1500 mg COD L⁻¹. Power density obtained from the samples, as a sole carbon source, ranged from 56 ± 3 W m⁻³ to 31 ± 1 W m⁻³ for the mesophilic and psychrophilic samples, respectively. Coulombic efficiencies ranged from 18 ± 1% to 12 ± 1% for the same samples. The relationship between the maximum voltage output and initial COD concentration appeared to follow saturation kinetics at the external resistance of 217 Ω. Chemical oxygen demand (COD) removal was over 90% and total phenolics removal was in the range of 30-75% for all samples tested, with a standard amount of 60 mg L⁻¹ total phenolics removed for every sample. Our results indicate that generating electricity from solution samples of anaerobic reactors utilizing grass silage is possible, opening the possibility for combination of anaerobic digestion with MFC technology for energy generation.     

Synergistic production of L-arabinose from arabinan by the combined use of thermostable endo- and exo-arabinanases from Caldicellulosiruptor saccharolyticus

The optimum conditions for the production of l-arabinose from debranched arabinan were determined to be pH 6.5, 75 °C, 20 g l⁻¹ debranched arabinan, 42 U ml⁻¹ endo-1,5-α-l-arabinanase, and 14 U ml⁻¹ α-l-arabinofuranosidase from Caldicellulosiruptor saccharolyticus and the conditions for sugar beet arabinan were pH 6.0, 75 °C, 20 g l⁻¹ sugar beet arabinan, 3 U ml⁻¹ endo-1,5-α-l-arabinanase, and 24 U ml⁻¹ α-l-arabinofuranosidase. Under the optimum conditions, 16 g l⁻¹l-arabinose was obtained from 20 g l⁻¹ debranched arabinan or sugar beet arabinan after 120 min, with a hydrolysis yield of 80% and a productivity of 8 g l⁻¹ h⁻¹. This is the first reported trial for the production of l-arabinose from the hemicellulose arabinan by the combined use of endo- and exo-arabinanases.     

Electrolyte effects on the intervalence transition within discrete binuclear cyano-bridged complexes. An estimation of activation free energy from static, optical and electrochemical data

A study of the metal-to-metal charge-transfer (MMCT) transition within the binuclear cyano-bridged complexes cis-[L¹³Co^III(μ-NC)Fe^II(CN)₅]⁻ (L¹³ = 12-methyl-1,4,7,10-tetraazacyclotridecan-12-amine), trans-[L¹⁴Co^III(μ-NC)Fe^II(CN)₅]⁻ (L¹⁴ = 6-methyl-1,4,8,11-tetraazacyclotetradecan-6-amine) and trans-[L¹⁵Co^III(μ-NC)Fe^II(CN)₅]⁻ (L¹⁵ = 10-methyl-1,4,8,12-tetraazacyclopentadecan-10-amine) has been carried out in electrolyte solutions at varying concentrations. Using these data, as well as the reaction free energies obtained from electrochemical measurements, the reorganisation and activation free energies for the forward and reverse thermal electron-transfer processes have been estimated. The changes of these parameters with the electrolyte concentration, as well as those of the energy of the maximum MMCT band and the reaction free energy, are mainly due to ion-pairing effects.     

Bioenergy potential of Ulva lactuca: biomass yield, methane production and combustion

The biomass production potential at temperate latitudes (56°N), and the quality of the biomass for energy production (anaerobic digestion to methane and direct combustion) were investigated for the green macroalgae, Ulva lactuca. The algae were cultivated in a land based facility demonstrating a production potential of 45 T (TS) ha⁻¹ y⁻¹. Biogas production from fresh and macerated U. lactuca yielded up to 271 ml CH₄ g⁻¹ VS, which is in the range of the methane production from cattle manure and land based energy crops, such as grass-clover. Drying of the biomass resulted in a 5-9-fold increase in weight specific methane production compared to wet biomass. Ash and alkali contents are the main challenges in the use of U. lactuca for direct combustion. Application of a bio-refinery concept could increase the economical value of the U. lactuca biomass as well as improve its suitability for production of bioenergy.     

Cross-linked succinyl chitosan as an adsorbent for the removal of Methylene Blue from aqueous solution

Removal of a basic dye (Methylene Blue) from aqueous solution was investigated using a cross-linked succinyl-chitosan (SCCS) as sorbent. The chemical structures of chitosan and its derivatives were testified by FT-IR. X-ray diffraction, DTG analysis and swelling measurements were conducted to clarify the characteristics of the chemically modified chitosan. The effect of process parameters, such as pH of the initial solution, and concentrations of dyes on the extent of Methylene Blue (MB) adsorption was investigated. The Langmuir isotherm model was used to fit the equilibrium experimental data, giving a maximum sorption capacity of 289.02 mg/g at 298 K. Kinetic studies showed that the kinetic data were well described by the pseudo-second-order kinetic model. Thermodynamic parameters such as enthalpy change (ΔH°), free energy change (ΔG°) and entropy change (ΔS°) were determined to be −25.32 kJ mol⁻¹, −6.76 kJ mol⁻¹ and −62.36 J mol⁻¹ K⁻¹, respectively, which leads to a conclusion that the adsorption process is spontaneous and exothermic.