Effect of Heat-Moisture Treatment on Equilibrium Moisture Content Models for Cassava Starches

The level of water contained in food products is known to affect several unit operations in food processing including drying, storage, and thermodynamics phenomena which are related to the sorption attributes of food. Heat-moisture treatment as an aspect of the thermodynamic properties of the food affects sorption phenomena and invariably the associated empirical models for the sorption behaviour. In this study, effect of heat-moisture treatment on sorption moisture isotherms for cassava starch at 27, 32, and 37oC, respectively was determined for selected cassava genotypes (TMS 97/4763 and TMS 98/0510) including its impact on equilibrium moisture content (EMC) empirical models. The moisture isotherms were sigmoidal indicating effect of temperature and show the influence of the heat pre-treatment. Six widely recommended three parameters sorption models were fitted to the EMC data from the gravimetric method. Desorption isotherms appears well fitted than adsorption isotherms. Analysis shows that due to the heat-moisture treatment, the Modified Oswin Equation (MOE) and Modified Halsey Equation (MHE) models are the preferred empirical equations for the modelling of the emc data for the cassava starches. Keywords: Cassava starch, equilibrium-moisture-content, heat-moisture treatment, sorption, isotherms

Effect of drying conditions on energy utilization during cocoyam drying

Cocoyam samples soaked in sodium metabisulphite (SM) and water blanched (WB) were oven dried at 50, 60 and 70° C and microwave power levels of 385, 540 and 700 W while untreated samples were sun dried. The effect of drying on selected properties of cocoyam was studied. The drying time generally reduced with increase in drying temperature and power level used. The use of SM pretreatment resulted in lower drying times compared with WB pretreatment. Effective moisture diffusivity values (Deff) for all the drying conditions varied from 5.27 x 10-8 to 2.07 x 10-6 m2/s and SM samples had higher values than WB samples.  Activation energy values for oven drying were 37.41 KJ/mol and 61.79 KJ/mol and that for microwave drying were 38.59 and 41.91W/g for SM and WB samples respectively.  The energy consumption varied from 125.1 to 142.8 kWh and 308 to 396.7 Wh while that of specific energy requirement varied from 86.2 to 106.5 kWh/kg and 1.49 to 2.03 KJ/kg water for oven drying and microwave drying respectively

Selection of Mass Transfer Models for Competitive Adsorption of Antibiotics Mixture from Aqueous Solution on Delonix regia Pod Activated Carbon

The selection of suitable mass transfer models that fit the adsorption of a mixture of antibiotics in aqueous solution onto activated carbon derived from Delonix Regia Pods (DRPs) was examined in this study. The ripe DRPs were cleaned, activated with KOH and then carbonised at 350 °C. The surface chemistry of the raw and the modified DRPs were characterised using Fourier Transform Infrared (FTIR), before being subjected to batch adsorption of a mixture of Amoxicillin (AMO), Tetracycline (TETRA) and Ampicillin (AMP)  under the effect of time (0-240 mins), and concentration (20-100 mg/l). The adsorption diffusion mechanisms of the process were analyzed. The spectra of the raw and modified DRP indicate the existence of hydroxyl groups alkanes, unconjugated ketone, carbonyl, and ester groups.  McKay has the highest  (0.9445) for the mass transfer diffusion model. This indicates that the adsorption rate of the selected antibiotics in the wastewater is regulated and monitored by the internal mass transport processes in accordance with a pore diffusion mechanism

Recikliranje ekspandiranog polistirena kao učinkovitog adsorbensa naftalena iz vodene otopine

Batch adsorption process factors [contact time (20–150 min), adsorbent dosage (0.5–1.5 g), adsorbate concentration (5–30 mg l–1), and agitation rate (100–250 rpm)] were optimised based on D-optimal Design under the Response Surface Methodology (RSM) of the Design-Expert Software (7.6.8) for the removal of naphthalene from aqueous solution using adsorbent developed from Acetylated Waste Expanded Polystyrene (AWEPs). The maximum adsorption capacity (5.6608 mg g–1) achieved was well fitted to Dubinin-Radushkevich Isotherm (R2 = 0.9949). The SSE (< 0.05) and ARE (< 4.0 %) indicated pseudo-second-order as the most suitable model. This research has demonstrated the effectiveness of the WEPs for the removal of naphthalene from the aqueous solution. This work is licensed under a Creative Commons Attribution 4.0 International License.Šaržni faktori procesa adsorpcije [vrijeme kontakta (20 – 150 min), doziranje adsorbenta (0,5 – 1,5 g), koncentracija adsorbata (5–30 mg l–1) i brzina miješanja (100–250 min–1)] optimizirani su na temelju D-optimalnog dizajna primjenom metodologije odzivne površine (RSM) programa Design-Expert (7.6.8) za uklanjanje naftalena iz vodene otopine pomoću adsorbenta razvijenog iz acetiliranog otpadnog ekspandiranog polistirena (AWEP). Ostvareni maksimalni adsorpcijski kapacitet (5,6608 mg g–1) dobro je prilagođen izotermi Dubinin-Radushkevich (R2 = 0,9949). SSE (< 0,05) i ARE (< 4,0 %) označili su pseudo-drugi red kao najprikladniji model. Ovo istraživanje pokazalo je učinkovitost WEP-a za uklanjanje naftalena iz vodene otopine. Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna

Optimization and Isothermal Studies of Antibiotics Mixture Biosorption From Wastewater Using Palm Kernel, Chrysophyllum albidum, and Coconut Shells Biocomposite

The presence of persistent pharmaceutical products in water bodies is a significant problem that obstructs wastewater reuse. This study investigated the adsorption process for removing the recalcitrant antibiotics, including tetracycline (TC), ampicillin (AMP), and amoxicillin (AMOX) from an aqueous solution using a composite biosorbent made from a mixture of palm kernel shell (PKS), Chrysophyllum albidum (CAS), and coconut shell (CS). Simplex centroid design in the Design of Expert (12.0.1.0) was applied to optimize the percentage composition (20-55%) of the composite biosorbent precursor and to remove TC-AMP-AMOX mixtures from the aqueous solution in a batch study. The equilibrium data were fitted to 12 isotherm models and analyzed statistically. The maximum adsorption capacity of 9.12 mg/g, 8.66 mg/g, and 7.11 mg/g was achieved for TC, AMP, and AMOX, respectively, using the biocomposite biosorbent with an optimal mixture of 55% PKS, 20% CAS, and 25% CS. The adsorption behavior of TC, AMP, and AMOX was well-described by the Langmuir/Elovich isotherm (R2=1.000), Hill-DeBoer (R2=0.9953), and Freundlich/ Halsey (R2=0.9898) models, respectively. The obtained results showed that the biocomposite PKS-CAS-CS leverages the individual adsorptive capacity of each constituent to enhance the adsorption process. Moreover, the composite biosorbent demonstrated excellent potential for removing recalcitrant pharmaceuticals from wastewater effectively