A. Ronda

Comparative study of isotherm parameters of lead biosorption by two wastes of olive-oil production

Batch isotherm studies were carried out on a laboratory scale: (i) to investigate the effectiveness to remove lead of two wastes (olive stone (OS) and olive tree pruning (OTP)), untreated and chemically treated; and (ii) to examine the applicability of various adsorption isotherms to fit the experimental data. Results from tests were analyzed using seven equilibrium isotherm correlations (Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Sips, and Toth equations). The sum of the squares of the errors was determined for each isotherm and the Langmuir equation provided the best fit. Chemical treatments increased the biosorption properties of these materials. The maximum biosorption capacities were: 6.33, 49.13, 14.83, and 38.93 mg g(-1) for untreated OS, HNO3-OS, H2SO4-OS, and NaOH-OS, respectively, and 26.72, 86.40, 72.78, and 123.80 mg g(-1) for untreated OTP, HNO3-OTP, H2SO4-OTP, and NaOH-OTP, respectively. Finally, the loss of mass for each waste (13.9, 14.3, and 36.8% for HNO3-OS, H2SO4-OS, and NaOH-OS and 35.1, 27.5, and 46.7% for HNO3-OTP, H2SO4-OTP, and NaOH-OTP, respectively) was taken into account and an effectiveness coefficient was determined for each adsorbent material.

Evaluation of biosorption of copper ions onto pinion shell

Abstract Biosorption of Cu(II) by pinion shell (PS) was investigated in batch and packed-bed systems. The biosorbent was characterized by elemental analysis, potentiometric titrations, surface area and pore size distribution, and Fourier transform infrared (FTIR) analyses. Potentiometric titrations and FTIR spectroscopy indicated the presence of functional groups in the PS, some of which were involved in the sorption process. Batch adsorption experiments were carried out as a function of solution pH, particle size, biosorbent dosage, contact time, and initial metal ion concentration. The rate of the biosorption process followed pseudo-second-order kinetics, while the sorption equilibrium data well fitted to the Langmuir and Freundlich isotherm models. The maximum monolayer Cu(II) biosorption capacity was 4.29 mg/g at 25°C. Finally, the dynamic biosorption studies were carried out using a packed-bed column and the main column parameters were determined. The present study suggests that the PS can be used as...

Kinetic analysis of pyrolysis and combustion of the olive tree pruning by chemical fractionation

This paper presents a kinetic analysis of thermal decomposition of olive tree pruning from its basic compounds in pyrolysis and combustion reactions. Experiments were performed by TGA under inert and oxidant conditions and results indicated that the decomposition of the olive tree pruning was related to the material composition. Pseudo-mechanistic models were proposed estimating the yield of pyrolysis on its basic compounds (hemicelluloses, cellulose and lignin). Validity and reliability of the proposed kinetic models were verified by the good fitting between the simulated and experimental curves (with values of R2 higher than 0.99 in most cases). Moreover, during the fractionation process, an acid fraction was obtained with great fuel properties, a high calorific value and a low residue after its combustion.

The scale-up of Cr3+ biosorption onto olive stone in a fixed bed column

AbstractIn this work, the scale up of olive stone columns for water purification, based on results from the biosorption of Cr(III) onto olive stone in a fixed bed column at pilot scale, was developed. Pilot-scale experiments were carried out in a fixed bed column to test the influence of various parameters (flow rate, bed depth, and initial chromium concentration) on breakthrough curves. Mathematical relationships were developed to describe Cr(III) biosorption in fixed bed column of olive stone at pilot scale. The results were found to be consistent with the previous published results obtained from laboratory scale. The bed depth service time (BDST), the Adams–Bohart, the Thomas, the Yoon and Nelson, and the Dose–Response models were used to analyze the experimental data and the model parameters were evaluated. The BDST allowed comparison between performances of pilot- and laboratory-scale columns, and Dose–Response model showed good agreement of the experimental breakthrough curves with model predictions...

Modeling of two up-flow fixed-bed columns in series for the biosorption of Cr6+ and Ni2+ by sugarcane bagasse

AbstractIn this work, results of the biosorption of Cr6+ and Ni2+ by sugarcane bagasse in two up-flow fixed-bed columns in series have been presented. The experimental data were adjusted for several kinetic models that describe the breakthrough curve obtained for a single column and for two columns in series. The Dose–Response model is the one that better adjusts the experimental data for the studied metals with a high correlation coefficient. Although with a single column, it is possible to reduce the metal concentrations under the requirements of Cuban normative, the use of two columns in series guarantees concentration nearly to 0 for two metals. So, the percentage removal with two columns in series were 98.2 and 92.8% for Cr6+ and Ni2+, respectively.

Scale-up of a packed bed column for wastewater treatment

After checking the success of the biosorption process to remove heavy metals from wastewater using olive tree pruning as a cheap biosorbent in the laboratory scale, the scale-up is necessary to progress towards industrial applications chance. The aim of this work was the study of the effect of scale-up in the process of biosorption of Pb(II) with olive tree pruning in a packed bed column. Experiments were performed using two different scale-up criteria and results obtained in both scales were compared. Similar parameters were obtained for each pair of equivalent tests, with a slightly advanced of the obtained breakthrough curves in the pilot plant. The experimental results were fitted by the Thomas model and the obtained mean values were KTh = 0.187 mL/min·mg and q0 = 20.59 mg/g for criterion 1 and KTh = 0.217 mL/min·mg and q0 = 20.27 mg/g for criterion 2. Finally, the mathematical model was applied to simulate industrial applications and it was obtained that under optimal operative conditions, a column according to the criterion 1 was able to operate 2.3 h, and a column according to the criterion 2 was able to operate for 3.6 h.

Physic-Chemical Characterization of a Waste from Olive Industry

In this work, a waste form olive industry was characterized in terms of its physical–chemical properties, which can be useful for its use in biosorption processes or in pyrolysis units. The characterization results showed that the solid presents a good size distribution to be use as biosorbent or as fuel, although it can be improve with a milled step. The initial moisture content is very high (around 40%), being one of the main characteristics of the solid that makes its direct use as a fuel difficult. However, the low sulfur value (< 0.1%) is very suitable from the environmental point of view, reducing SO2 emissions. The results of the proximate analysis showed a high content of ashes and the gross calorific value within the range of most biomass waste, was 5100 kcal/kg.