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1

Natural coagulation as an alternative to raw water treatment

Villabona-Ortíz Ángel, Tejada-Tovar Candelaria, Ortega-Toro Rodrigo, Licona Dager Natalia, Millan Anibal Marta

Journal of Water and Land Development

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2023

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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.

2

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

Tejada-Tovar Candelaria, Bonilla-Mancilla Humberto, Ortega-Toro Rodrigo, Villabona-Ortíz Ángel, Díaz-Illanes Manuel

Journal of Water and Land Development

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2022

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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.

3

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

Villabona-Ortíz Ángel, Tejada-Tovar Candelaria, Ortega-Toro Rodrigo, Peña-Romero Keily, Botello-Urbiñez Ciro

Journal of Water and Land Development

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2022

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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

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

Villabona-Ortíz Ángel, Tejada-Tovar Candelaria, Ortega-Toro Rodrigo, Peña-Romero Keily, Botello-Urbiñez Ciro

Journal of Water and Land Development

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2022

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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.

5

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

Tejada-Tovar Candelaria, Villabona-Ortíz Ángel, Gonzalez-Delgado Angel Darío

Journal of Water and Land Development

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2021

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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.

6

Effect of temperature in removing of anions in solution on biochar using Zea mays stalks as a precursor

Villabona-Ortiz Ángel, Tejada-Tovar Candelaria, Ortega-Toro Rodrigo

Journal of Water and Land Development

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2021

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no. 50

64--68

EN

Biochar was prepared from corn (Zea mays) stalks and impregnated with sulfuric acid. The biomass was impregnated for 24 h with a 50% solution of H2SO4 with impregnation ratios 1:2 (B 1:2) and 1:3 p/v (B 1:3); then, it was carbonized in a muffle furnace at 520°C for 30 min with a 10°C per min ramp. The adsorption capacity to remove anions (nitrate, sulfate, and phosphate) in an aqueous solution was evaluated by varying the temperature. The adsorption mechanism was studied by determining the thermodynamic parameters: Gibbs free energy (ΔGº), enthalpy (ΔHº) and entropy (ΔSº) standard. The biochars were characterized by Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) analysis and were found to exhibit a heterogeneous surface and porous nature, with C, O, S, and Si. The experiments in the batch system showed the best performance of B 1: 2 in the removal of the three anions occurred at 303 K, while B 1: 3 had the best performance at 298 K. From the thermodynamic parameters, it was found that the removal processes are endothermic, their mechanism is by chemisorption. It is concluded that synthesized biochar is an excellent alternative to removing nutrient anions present in the solution.

7

Comparative assessment of Al2O3 modified biomasses from agricultural residues for nickel and cadmium removal

Herrera-Barros Adriana, Tejada-Tovar Candelaria, Gonzalez-Delgado Angel D.

Journal of Water and Land Development

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2021

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no. 49

29--34

EN

The biodiversity of aqueous environments has been affected due to the disposal of wastewater highly contaminated with heavy metal ions, causing much damage to ecosystems. These pollutants are very toxic and bioaccumulate in living organisms. This work attempts to evaluate the adsorption of nickel ad cadmium ions using three biomasses from agricultural residues (corn cob – CC, orange peel – OP, and oil palm bagasse – PB) modified with alumina nanoparticles. The biomasses were characterized via compositional analysis and a point of zero charges to quantify the presence of lignin, cellulose, hemicellulose, and the feasible pH, taking advantage of the biomass charge. After modification with Al2O3 nanoparticles. The resulting adsorbents were characterized via FT-IR analysis to identify the functional groups that most contributed to the adsorption performance. Furthermore, the influence of Al2O3 nanoparticles was analysed on the adsorption capacities of the evaluated biomasses using batch systems at a temperature of 25°C and pH 6. All biomasses displayed a high content of cellulose, estimating a weight percentage of about 19.9%, 14.3%, and 13.1% for PB, OP, and CC samples, respectively. The FT-IR spectrum confirmed hydroxyl and carboxyl functional groups, which contribute to enhancing the adsorption capacities of the modified biomasses. Functional adsorption capacity was observed for all biomasses after modification with Al2O3 nanoparticles, achieving at pH 6.0 a cadmium removal from 92% (CC-Al2O3 and PB-Al2O3) up to 95.8±0.3% (OP-Al2O3). In nickel ions, it was estimated a broader adsorption capacity at pH 6.0 of about 86±0.4% after using the CC-Al2O3 sample, 88±0.1% for the PB-Al2O3 adsorbent, and 98±0.2% for the OP-Al2O3 sample, confirming the suitability of these Al2O3-modified biomasses for the removal of heavy metal ions.