Insight into the Sorption and Activation Energy Phenomenon of Kenaf Shive Sorbents in Crude Oil/Water Mixture

The secondary effect discovery of synthetic sorbents opened another research direction for many field of studies. However, the sorption parameters of lignocellulosic sorbents are rarely reported most importantly, kenaf shive. This paper centered at the sorption behavior of optimized kenaf shive sorbents using Response Surface Methodology (RSM) via surface deposit technique. Five-level Central Composite Design (CCD) experimental matrix was used to analyze the effect of particle sizes (125-1000 µm), stirring time (5-30min) and methyltrimethoxysilane (MTMS) concentration (5-20% v/v) as individual and combined variables process in the developed sorbents. The unmodified shive was compared with the modified, and it reveals a positive shift in the sorption capability. Instrumental analysis such as FTIR (Fourier Transform Infra-Red), DT-TGA (Differential Thermal-Thermogravimetric analysis) and BET (Brunaure-Emmett-Teller) were carried out on the optimized sorbent and the results were in conformity with the sorption results. The sorption behavior deployed fits the pseudo-first-order and Langmuir isotherm with regression coefficient R2=0.9496 and R2=0.9400. The sorption property was found to be spontaneous and exothermic, however, the activation energy studies shows physic-sorption phenomenon with 25.3 kJmol-1 and R2=0.9360.

A Novel Combined Treatment Process of Hybrid Biosorbent–Nanofiltration for Effective Pb(II) Removal from Wastewater

The untreated effluents discharged by different industries, such as metallurgy, fertilizers, pesticide, leather, mining, electroplating, surface finishing, aerospace, and electroplating, have increased the risk of the contamination of bodies of water by heavy metals. Herein, hybrid biosorbent–nanofiltration processes for Pb(II) removal from wastewater was studied. The hybrid biosorbent was prepared from date seed waste and Ganoderma lucidum. Hybrid biosorbent characterization was performed by SEM and FTIR. SEM micrographs showed that the HB surface is irregular. For the adsorption studies, various sorption parameters were optimized. The maximum biosorption capacity of immobilized heat-inactivated hybrid biosorbent was 365.9 mg/g, with the Langmuir isotherm model to present the best fit. Desorption experiments were conducted for regenerating immobilized heat-inactivated hybrid biosorbent for three consecutive cycles using different desorption agents, with acetic acid to be the optimum. Going a step further, nanofiltration was also applied as a post-treatment process to elevate the remediation effectiveness for wastewater of high Pb(II) initial concentrations. The reasonably low cost and high removal of Pb(II) make hybrid biosorbent–nanofiltration processes a prosperous and potentially attractive hybrid approach against heavy-metal-polluted wastewater.

Use of Garlic Processing By-Products to Remove Pollutants from Aqueous Media

The paper summarized the literature data on using ground peels, outer leaves, and garlic roots (Allium sativum L.) as sorption materials to remove various metal ions, dyes, and antibiotics from aqueous media. This paper provides brief information on the amount of waste generated from processing garlic, its chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that garlic residue sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutant’s adsorption isotherms in most cases, and the kinetics of the process more accurately describes the pseudo-second-order model. It was shown that garlic peels and steam are good precursors for activated carbons production.

Review of Almond (Prunus Dulcis) Shell Use to Remove Pollutants from Aquatic Environments

We summarized the literature data on using ground almond (Prunus dulcis) green hull and shell as sorption materials to remove various metal ions, dyes, and some organic compounds from aqueous media. This paper provides brief information on the amount of waste generated from processing almonds, their chemical composition, and ways of reuse. It gives the adsorption processes parameters and the values of sorption parameters for the studied pollutants. It was shown that almond shells’ sorption characteristics for various pollutants could be increased by chemical modification with various chemical reagents. It was determined that the Langmuir model more accurately describes the pollutants adsorption isotherms in most cases, and the kinetics of the process in all cases follows the pseudo-second-order model. It was shown that almond hulls and shells are a good precursor for activated carbons production.

Influence of non-equilibrium sorption on the vertical migration of 137Cs in forest mineral soils of Fukushima prefecture

<p>Vertical migration of radiocesium is a key issue in soils impacted by Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. Among radioactive substances deposited on terrestrial ecosystems, <sup>134</sup>Cs (with half-life 2.07 years) and <sup>137</sup>Cs (with half-life 30.2 years) were dominant and have by far the most radiological significance.</p><p>This work investigates the importance of non-equilibrium sorption on the vertical migration of <sup>137</sup>Cs in field conditions. The equilibrium-kinetic (EK) sorption model was selected as a non-equilibrium parameterization embedding the K<sub>d</sub> approach. It supposes the existence of two types of sorption sites. The first sites are at equilibrium with solution; whereas for the second sites, kinetics of the sorption and desorption are taken into consideration.</p><p>We focused our study on four <sup>137</sup>Cs soil contamination plots measured in a young cedar stand situated around 35 km northwest of the FDNPP. Profiles were sampled at four different dates (2013, 2014, 2016, and 2018) by measuring <sup>137</sup>Cs activity in both organic (humus + litter layer) and mineral soil layers reaching a maximum depth of 20cm.</p><p>To successfully simulate the <sup>137</sup>Cs transfer throughout these soil profiles, the input flux at the top of the mineral soil surface was reconstructed from global monitoring data from the forest stand and a first-order compartment model for the organic layer.</p><p>Our results showed that the inclusion of non-equilibrium sorption slightly improves the realism of simulated <sup>137</sup>Cs profiles compared to the equilibrium hypothesis. While both models were able to reproduce the overall vertical distribution throughout the profiles, the persistent contamination at the surface was closer to the measured value with the EK approach. As a consequence, the K<sub>d</sub> model overestimated the contamination into deeper layers and therefore overestimated the migration velocity of <sup>137</sup>Cs. Fitted sorption parameters suggested a fast sorption kinetic (1 - 7 hours) and a pseudo-irreversible desorption rate (3.2 - 3.4 x 10<sup>6</sup> years), whereas equilibrium sorption (4.0 x 10<sup>-3</sup> L kg<sup>-1</sup> on average) only affected a negligible portion of <sup>137</sup>Cs inventory.</p><p>To further distinguish the models behaviors, short and long term simulations were conducted. By June 2011, EK parameters fitted on our plots realistically reproduced different profiles measured in the same forest study site. Predictive modeling of <sup>137</sup>Cs profiles in soil suggested a strong persistence of the surface <sup>137</sup>Cs contamination by 2030, with exponential profiles consistent with those reported after the Chernobyl accident.</p><p>These results prove that the choice of the sorption model is critical in post-accidental situations. An equilibrium approach can result in an underestimation of <sup>137</sup>Cs residence time in the surface. Whereas a kinetic approach, by distinguishing different sorption and desorption rates, is able to reproduce the slow evolution of <sup>137</sup>Cs soil profiles with time that is already observed in the case of Chernobyl contaminated areas 30 years after the accident. Non equilibrium sorption parameters can be partially inferred from in situ measurements. However, further experiments in controlled conditions are required to better estimate the sorption parameters and to identify the processes behind non-equilibrium sorption.</p>

Synthesis of Ethylenediaminetetraacetic Acid Disodium Salt Functionalized Magnetite/Chitosan Nanospheres for the Highly Efficient Removal of Methylene Blue

In this paper, novel Ethylenediaminetetraacetic acid disodium salt (EDTA) functionalized magnetite/ chitosan nanospheres (Fe3O4/CS-EDTA) are synthesized by combining solvothermal method and chemical modification, and they are further applied as a kind of adsorbent to eliminate dye of methylene blue (MB) from wastewater. The properties as well as structure exhibited by the fabricated adsorbent are characterized through FTIR, XRD, TG and TEM, together with VSM. The impact exerted by sorption parameters (time of contact, initial dye concentration, temperature, etc.) on the adsorptions were evaluated in batch system. These results demonstrated that our magnetic materials held the adsorption capacity for MB of 256 mg g−1 (pH = 11), and the kinetic model of pseudo-second-order and the Langmuir model could make an effective simulation regarding the adsorption kinetics and isotherm, respectively. Besides, the external magnetic field can assist in easily separating dye adsorbed Fe3O4/CS-EDTA from solution for regeneration. The removal efficiency of recycled adsorbents remained above 92% in the 5th adsorption/desorption cycle. These superioritiesmake Fe3O4/CS-EDTA a high-efficientmultifunctional adsorbent for removing dyes from wastewater.

Phosphorus Sorption Characteristics of Luvisols and Nitisols in North Ethiopian Soils

Crop response to phosphorus (P) application is often erratic in most acidic soil types. The main processes for P losses from agricultural fields are fixation, crop removal, erosion, surface runoff, and subsurface leaching. The purpose of this experiment was to evaluate adsorption properties of selected soils, determine the external phosphorous requirements (EPRs) of the soils, and identify factors contributing to P sorption in two soils in North Ethiopia. In this experiment, separately weighed 1 g soil samples were equilibrated with KH2PO4 at rates of 0.5, 5, 10, 20, 30, 40, and 50 mg PL−1. The P sorption data were fitted well with both Langmuir and Freundlich models with average r2 values of 0.91 and 0.88, respectively. The adsorption maximum (Xm) of the Langmuir isotherm ranged from 588.20 mg P kg−1 soil in Luvisols to 833.3 mg P kg−1 soil in Nitisols. The EPRL values ranged between 86.20 to 93.28 mg P kg−1 for soils of the study area. Among the soil properties, clay content and Ex. Al were positively correlated with Xm. The path analysis revealed that clay, pH, and Av. P had a direct effect on P sorption parameters. The EPRL of the studied soils was 3.44 to 3.6 times greater than the blanket P fertilizer rate recommendation. It is concluded that P sorption models can effectively be used to discriminate soils based on P fixation ability. The result further indicates that the current P fertilizer application rate of 50 kg P ha−1 being practiced across all soil types should be revised after validating the models and EPR values estimated in this study for each soil both under greenhouse and in-the-field conditions.

Derivation of pesticide aged sorption parameters from laboratory incubation data

The results of the incubation laboratory experiment showed that the decomposition of cyantraniliprole is bi-phasic and the rapid decomposition in the period after the application of the pesticide is accompanied by a subsequent slowdown of this process. The use of the biexponential equation increased the accuracy of the description of the dynamics of decomposition of cyantraniliprole, as evidenced by the static indices. The bi-exponential equation coefficients were used to calculate the parameters of non-equilibrium sorption. The obtained parameters served as input data for the PEARL model. Modelling the migration of cyantraniliprole with considering aged sorption, showed a significant decrease in the predicted concentrations of the pesticide in percolate.