Modeling and optimization of laying hen manure drying process to reduce protein and ammonium-N losses by adding sodium bentonite and wheat straw.

Laying hen manure (LHM) is a major source of pollution due to its high nitrogen (N) and moisture content (MC). Therefore, reducing the MC of LHM is necessary to retain its recyclable value and reduce environmental pollution. One effective way is by incorporating sodium bentonite (SB) and wheat straw (WS) as amendments in the LHM. This work aimed to optimize the drying conditions of LHM and investigate the effect of SB and WS utilization on the dehydration rate, reduction of crude protein (CP), and reduction of ammonium-N (N [Formula: see text] -N). The response surface methodology (RSM) was used to optimize these processes. For this purpose, two sets of experiments (drying of LHM with and without SB and Ws) were designed. The independent parameters were air temperature (70, 80, and 90 °C), air velocity (1, 1.5, and 2 m s-1), layer thickness (5, 10, and 15 mm), SB (2%, 4%, and 6%), and WS (3%, 7.5%, and 12%). The results indicated that temperature and WS had the most significant influence on all responses. To maximize the dehydration rate and minimize the reduction of CP and N [Formula: see text] -N, the optimal conditions were a temperature of 78 °C, air velocity of 1 m s-1, and layer thickness of 5 mm in the first set of experiments, and a temperature of 80 °C, air velocity of 1.5 m s-1, layer thickness of 11 mm, 6% SB, and 12% WS in the second set of experiments. Under the optimum conditions, LHM treated with 6% SB and 12% WS retained 10% more CP and 58% more N [Formula: see text] -N than untreated LHM. Therefore, according to the obtained results, SB and WS are recommended as additives to reduce the CP and N [Formula: see text] -N losses of LHM during the drying process.

Intelligent modeling and experimental study on methylene blue adsorption by sodium alginate-kaolin beads.

As tighter regulations on color in discharges to water bodies are more widely implemented worldwide, the demand for reliable inexpensive technologies for dye removal grows. In this study, the removal of the basic dye, methylene blue, by adsorption onto low-cost sodium alginate-kaolin beads was investigated to determine the effect of operating parameters (initial dye concentration, contact time, pH, adsorbent dosage, temperature, agitation speed) on dye removal efficiency. The composite beads and individual components were characterized by a number of analytical techniques. Three models were developed to describe the adsorption as a function of the operating parameters using regression analysis, and two powerful intelligent modeling techniques, genetic programming and artificial neural network (ANN). The ANN model is best in predicting dye removal efficiency with R2 = 0.97 and RMSE = 3.59. The developed model can be used as a useful tool to optimize treatment processes using the promising adsorbent, to eliminate basic dyes from aqueous solutions. Adsorption followed a pseudo-second order kinetics and was best described by the Freundlich isotherm. Encapsulating the kaolin powder in sodium alginate resulted in removal efficiency of 99.56% and a maximum adsorption capacity of 188.7 mg.g-1, a more than fourfold increase over kaolin alone.

Enhanced selectivity and performance of heterogeneous cation exchange membranes through addition of sulfonated and protonated Montmorillonite.

Novel heterogeneous cation exchange membranes, based on poly (ether sulfone) and cation exchange resin, were prepared with the addition of protonated and sulfonated Montmorillonite (MMT) nanoparticles. Detailed investigations were then carried out studying the morphology, physical properties and the performance of membranes. It is observed that addition of MMT, leads to a substantially better distribution of ion exchange resin in the polymer matrix. This leads, at low loadings of MMT (0.5 wt.%), to membranes that are more hydrated, more hydrophilic and with higher ion exchange capacities. Especially at these low MMT loadings, substantially better membrane performance is observed, with higher permselectivities, lower areal resistances and increased ion transport during electrodialysis. A very surprising effect is that the addition of MMT has a strong effect on the selectivity of the membranes, especially towards Mg2+. A high affinity of the nanoclay towards Mg2+, selectively slows down Mg2+ transport through the nanoclay containing membrane. At low MMT loadings this leads to a much higher areal resistance for Mg2+, while for Na+ and Ca2+ the areal resistance is decreased. This leads to resistance based selectivities of 5.5 for Na+/Mg2+ and 4.5 for Ca2+/Mg2+. Under more challenging electrodialysis operation selectivities become lower, but persist at 2.6 for Na+/Mg2+ and 2.04 for Ca2+/Mg2+, outperforming commercial Ralex membranes. Overall, the protonated clay leads to slightly better membrane performances and selectivities than the sulfonated clay, likely due to a better compatibility with PES.

An investigation into electrochemical properties of poly(ether sulfone)/poly(vinyl pyrrolidone) heterogeneous cation-exchange membranes by using design of experiment method.

Poly(ether sulfone) (PES)/poly(vinyl pyrrolidone) (PVP) blend heterogeneous cation exchange membranes were prepared by solution casting technique using dimethylformamide as solvent and cation exchange resin powder as functional groups agent. In this study, Taguchi experiment design method was employed for investigating the effects of controlling variables including polymer binder (PVP + PES) to total casting solution ratio, blend ratio of polymer binders (PVP to PES), resin to polymer binder ratio, and casting temperature on electrochemical characteristics of PES/PVP heterogeneous membranes. To this aim, each factor was considered at 4 different levels and therefore, 16 experiments were designed. To improve the quality of the membranes ultrasonic was used for appropriate dispersing of resin particles in the matrix of the membranes. According to the results, the averaged maximum values of 1.535 meq/g and 46.6 mV were obtained for IEC and membrane potential, respectively. Also, the highest obtained value of ion permeability tests was equal to 1.33 m/s. Finally, the synthesis conditions was optimized by considering the IEC and membrane potential as the objective functions which gave the values of 1.55 meq/g and 1.39 m/s for IEC and membrane potential, respectively, which proved that the synthesized membrane can be considered as a promising heterogeneous membrane.

Optimization of Pb(II) ions adsorption on nanohydroxyapatite adsorbents by applying Taguchi method.

This paper presents an optimization approach for the removal of lead ions (Pb+2) by nano-hydroxyapatite powder form adsorbents that were produced from bovine bone by mechanical activation method. The Taguchi method was implemented for designing the experiments by considering four controllable factors including (1) ball milling time (A), (2) the initial concentration of lead ions (B), (3) initial pH of the solution (C); and (4) the adsorbent dosage (D), each factor at four different levels. According to the ANOVA analysis results, the removal efficiency of the lead ions was predominantly influenced by the adsorbent dosage (38.2%) and the initial lead ions concentration (23.64%), whereas the effect of initial pH of the solution was ignorable and the ball milling time had a mild contribution of 14.79%. The total optimum adsorptive lead ions removal of 100% was achieved by optimization process at operating conditions of Co = 180 mg L- 1, ball milling time = 2 h, pH = 3, and adsorbent dosage = 0.15 g. The Langmuir isotherm model fitted to the equilibrium results with good accuracy and a maximum sorption capacity of 200 mg g-1 was predicted by the model for the hydroxyapatite adsorbent ball milled for 2 h.