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1

The kinetics, thermodynamics and equilibrium study of nickel and lead uptake using corn residues as adsorbent

100%

Tejada-Tovar C. , Villabona-Ortíz Á. , Gonzalez-Delgado A. D.

Journal of Water and Land Development

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2021

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tom no. 48

197--204

EN

Agricultural residues rich in lignocellulosic biomass are low-cost and sustainable adsorbents widely used in water treatment. In the present research, thermodynamics, kinetics, and equilibrium of nickel(II) and lead(II) ion biosorption were studied using a corncob (Zea mays). The experiments were performed in a batch system evaluating the effect of temperature and dose of adsorbent. Langmuir and Freundlich isotherms were used to study the equilibrium. Thermodynamic and kinetic parameters were determined using kinetic models (pseudo-first order, pseudo-second order, Elovich). Biosorbent characteristics were studied by Fourier-transform infrared spectroscopy, Scanning Electron Microscopy and Energy-dispersive X-ray spectroscopy. It was found that the hydroxyl, carboxyl, and phenolic groups are the major contributors to the removal process. Besides, Pb(II) ions form micro-complexes on the surface of the biomaterial while Ni(II) ions form bonds with active centers. It was found that the highest Ni(II) removal yields were achieved at 0.02 g of adsorbent and 70°C, while the highest Pb(II) removal yields were achieved at 0.003 g and 55°C. A maximum Ni(II) adsorption capacity of 3.52 mg∙g–1 (86%) and 13.32 mg∙g–1 (94.3%) for Pb(II) was obtained in 250 and 330 min, respectively. Pseudo-first order and pseudo-second order models best fit experimental data, and Langmuir and Freundlich models well describe the isotherm of the process. Thermodynamic parameters (ΔH0, ΔG0, ΔS0) suggest that the adsorption process of both cations is exothermic, irreversible, and not spontaneous.

2

Predictive modelling of a rapid stratified bed filter for turbidity removal from surface water

100%

Tejada-Tovar C. N. , Villabona-Ortíz Á. , López-Barbosa D.

Journal of Water and Land Development

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2022

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tom no. 53

192--202

EN

The objective of the present work was to evaluate the hydrodynamic behaviour of a stratified bed filtration column consisting of 4 cm of sand and 2 cm of limestone to remove turbidity and measuring the head loss through the filter in several runs. In this study, two types of sand were used as filtering bed material, one fine and one medium. Crushed limestone was also available. These materials were characterized to determine the average particle diameter, porosity, and permeability coefficient. These were respectively 1.7∙10-4 m, 336.96 and 0.68 m∙day-1 for fine sand, 3.3∙10-1 m, 654.24 and 2.59 m∙day-1 for the medium sand and 1.26∙10-3 m, 388.8 and 8.64 m∙day-1 for crushed limestone. Using these materials, hydrodynamic analyses were carried out using clean water under rapid filtration conditions. In these analyses, different filtration rates were determined to be used in each experiment. Once the filtration rates were determined, the filtration analysis was performed with synthetic turbid water prepared at 8 NTU using tap water and bentonite. From the results obtained, a predictive model was developed based on total head losses for the evaluated filter, maintaining the rapid filtration condition. As a result, a turbidity removal efficiency of 97.7% was obtained with a total head loss of 17.8 cm at a filtration rate of 153 m·day-1 . The developed model predicted head loss as a function of operating time, filtration rate, and filter depth to maximise turbidity removal. The model showed excellent prediction accuracy with R2 of 0.9999, which indicates that the model predictions are not biased. It was concluded that, due to the porosity of these materials, a stratified bed of sedimentary rocks has a great potential to be used in surface water filtration processes, which implies that it could be used at the rural community level as a form of water treatment, since the material is a readily available, maintenance is simple and low cost, and installation and operation are effortless.

3

Impact of temperature, bed height, and particle size on Ni(II) removal in a continuous system: Modelling the break curve

88%

Villabona-Ortíz Á. , Tejada-Tovar C. , Ortega-Toro R. , Peña-Romero K. , Botello-Urbiñez C.

Journal of Water and Land Development

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2022

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tom no. 52

257--264

EN

The objective of this research was to evaluate the adsorption capacity of the shell biomass (Dioscorea rotundata), taking into account the impact of temperature, bed height, and particle size on the removal of nickel(II) ions in aqueous solution in a continuous fixed-bed column system; performing the modelling of the break curve. The biomass was characterised by SEM-EDS analysis. The analysis found that it represents a rough, heterogeneous structure, rich in carbon and oxygen, with mesopores, and is suitable for removing heavy metals. It also determined the optimum parameters of the bed height, particle size, and temperature, keeping the pH and the initial concentration of the solution constant. The results revealed that the bed height and the particle size are the two most influential variables in the process. Ni(II) removal efficiencies range between 85.8 and 98.43%. It was found that the optimal conditions to maximise the efficiency of the process are temperature of 70°C, 1.22 mm particle size, and 124 mm bed height. The break curve was evaluated by fitting the experimental data to the Thomas, Adams-Bohart, Dose-Response, and Yoon-Nelson models, with the Dose-Response model showing the best affinity with a coefficient of determination R2 of 0.9996. The results obtained in this research showed that yam shell could be suggested as an alternative for use in the removal of Ni(II) ions present in an aqueous solution in a continuous system.

4

The elimination of lead(II) ions in a solution by bio-adsorption: Kinetics, equilibrium, and thermodynamics

88%

Tejada-Tovar C. , Bonilla-Mancilla H. , Ortega-Toro R. , Villabona-Ortíz Á. , Díaz-Illanes M.

Journal of Water and Land Development

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2022

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tom no. 53

118--127

EN

In the present study, the removal capacity of Pb(II) ions was investigated using the biomass of dried cattle manure in an aqueous solution. The biomaterials were characterized using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) techniques. The results reveal that the adsorption mechanism may be associated with the interaction between Pb(II) ions and functional groups through aggregation, coordination, ion exchange, microprecipitation, oxidation, and hydrophobicity. The bio-adsorption of the metal was analysed in discontinuous tests; the effect of temperature, pH, agitation, and adsorbent dose was evaluated. The maximum adsorption capacity was determined at pH 7.5, 18°C and 200 rpm. The bio-adsorption of Pb(II) was best fitted to the pseudo-second order model. The experimental data of the isotherm were adjusted to the models of Langmuir, Freundlich and Dubinin-Radushkevich; while Langmuir’s model related better to the experimental data forming a single layer at saturation. The rate of adsorption was rapid, reaching equilibrium after 25 min and removal of 96.8%. Thermodynamic parameters determined that the process was viable, spontaneous, and exothermic. The present study contributes mainly to demonstrating that a biomaterial prepared from bovine manure is a promising adsorbent for heavy metals such as Pb(II). It also reduces the environmental impact of this waste through the generation of greenhouse gases in countries that maintain intensive livestock. Another important aspect is the reduction of the micro- and macronutrients accumulation in soil and contamination of surface waters and aquifers by runoff and seepage during rainy periods.

5

Natural coagulation as an alternative to raw water treatment

88%

Villabona-Ortíz Á. , Tejada-Tovar C. , Ortega-Toro R. , Licona Dager N. , Millan Anibal M.

Journal of Water and Land Development

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2023

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tom no. 56

21--26

EN

The availability of drinking water is one of the several problems humans face, considering that its availability is reduced to 0.80% of the existing fresh water. Then, coagulation-flocculation is a stage of this treatment. It is a process that agglomerates the suspended particles in a larger (floc) that could be separated by sedimentation and filtration processes to make the water drinkable. So, this work aimed to evaluate the effect of the dose of coagulant of yam starch (Dioscorea rotundata) and the speed of agitation in the turbid water treatment process. For which the yam starch was extracted by implementing two methods which were NaOH and H2O, using centrifugation at 1500 rpm for 10 min, and adjusting the pH with HCl and NaOH 0.20 M, for later determining the effect of agitation speed (rpm) and coagulant concentration (ppm) on the percentage of turbidity removal, pH, and colour, to be compared with a synthetic coagulant. A yield of 42.60% was found in the wet base. The natural coagulants extracted with NaOH presented better turbidity removal, with a percentage of 92.48% at an agitation speed of 40 rpm and a concentration of 250 ppm. It can be concluded that natural yam coagulant can be recommended for use in the coagulation stage in the raw water treatment process for subsequent conversion to drinking water.

6

Chrome(VI) ion biosorption modelling in a fixed bed column on Dioscorea rotundata hull

88%

Villabona-Ortíz Á. , Tejada-Tovar C. , Ortega-Toro R. , Peña-Romero K. , Botello-Urbiñez C.

Journal of Water and Land Development

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2022

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tom no. 53

202--209

EN

This work aimed to evaluate the yam peel in a bed column packaged as a chromium(VI) ion adsorbent in an aqueous solution. Yam peel was used as adsorbent, prior washing, drying, size reduction, and selection. The experimental work consisted in determining the effect of bed depth, particle size, and temperature, keeping inlet flow = 0.75 cm3∙s-1, pH = 2 and initial concentration of 100 mg∙dm-3. The Adsorption Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS) analysis on yam (Dioscorea rotundata) peel showed a heterogeneous, porous structure, with functional groups characteristic in lignocellulosic materials. It was analysed regarding the influence of temperature, bed height, and adsorbent particle size on the removal efficiency; it was found that the decrease of particle size and the increase of the bed height favour the elimination of the metallic ion, with removal rates between 92.4 and 98.3%. The bed maximum adsorption capacity was 61.75 mg∙g-1, and break time of 360 min. The break curve’s adjustment to the Thomas, Yoon-Nelson, Dose-Response and Adams-Bohart models was evaluated, concluding that the Yoon-Nelson and Dose-Response models best described the behaviour of the break curve with a coefficient of determination (R2) of 0.95 and 0.96, respectively. The results show that the bio-adsorbent studied can be used to eliminate Cr(VI) in a continuous system.