Batch Experimental System Research Articles

Modelling of lead removal from battery industrial wastewater treatment sludge leachate on cement kiln dust by using Elman's RNN

In this study, an Elman type recurrent neural network (RNN) was employed to develop a prediction model for lead removal from industrial sludge leachate using cement kiln dust. The leaching characteristics of industrial sludge were observed through the toxicity characteristics leaching procedure (TCLP). Dosage, contact time, and temperature were considered as independent experimental factors. A comparison between the model results and experimental data showed that the Elman's RNN model is able to predict lead removal from industrial sludge leachate. The outcomes of suggested Elman's RNN modelling were then compared to batch experimental studies. The results show that industrial sludge leachate using cement kiln dust is an efficient sorbent, and Elman's RNN is dynamic in nature and is able to model the batch experimental system.

Kinetic and Thermodynamic Analysis of Anthocyanin Thermal Degradation in Acerola (Malpighia emarginata D.C.) Pulp

Acerola fruit (Malpighia emarginata D.C.) is in high demand worldwide because of its great taste, and also due to its substantial content of anthocyanins, associated with other health compounds. This paper provides experimental and simulation results of anthocyanin thermal degradation in acerola pulp during industrial processing. Kinetic and thermodynamic parameters were evaluated in a batch experimental system and an appropriated mathematical modeling was developed to simulate the anthocyanin losses in a tubular heat exchanger as industrial pasteurization system. Our finds indicate activation energy of degradation equals 68 kJ/mol, suggesting a strong dependency of temperature. Moreover, simulations showed that in real heating situations, the losses of anthocyanins in acerola pulp could be very small, less than 1%, at 20 s of residence time and 70C, if appropriated operational conditions were set. Therefore, this present research provides not only experimental and simulation data of anthocyanin degradation, but also a useful tool to predict the minimal losses during processing. Practical Applications The kinetic and thermodynamic analysis of this work can be used to estimate the anthocyanin losses during industrial processes. The case study of this paper concerns on tubular systems. However, the kinetic parameter estimation and the degradation rate also obtained can be used in any industrial situation by an appropriate modeling adaptation, for example, considering the common plate systems.

Arsenate Adsorption from Aqueous Solution onto Fe(III)-Modified Crop Straw Biochars

Abstract Biochars generated from peanut straw (PS) and rice straw (RS) were modified using Fe(III), which were then evaluated for As(V) adsorption in batch experimental systems. Results indicated that noncrystalline Fe hydroxides formed on the biochars during modification, reducing the negative charge on the biochar surface, and consequently the electrostatic repulsion to As(V) adsorption. Adsorption capacities of unmodified biochars for As(V) were low, but Fe(III) modification considerably enhanced As(V) adsorption by the biochars. The Langmuir isotherm fit the adsorption data well and could be used to describe As(V) adsorption by the Fe(III)-modified biochars. Maximum adsorption capacities for As(V), calculated using the Langmuir equation, were 33.7 g/kg for Fe(III)-modified PS biochar and 27.0 g/kg for Fe(III)-modified RS biochar at pH 5.0. As(V) adsorption capacities of both Fe(III)-modified biochars were much greater than that for goethite (13.1 g/kg) at pH 5.0. As(V) was mainly adsorbed by the Fe(II...

Prediction of adsorption efficiency for the removal malachite green and acid blue 161 dyes by marble sludge dust using ANN

<div> <p>In the present study, batch adsorption studies were performed for the removal of malachite green and acid blue 161 dyes from aqueous solutions by varying parameters such as contact time, waste marble dust amount, initial dye concentration and temperature. The equilibrium adsorption data were analyzed by Langmuir, Freundlich and Temkin adsorption isotherm models. The Langmuir and Freundlich adsorption models agree well with experimental data. The pseudo-second order, intraparticle intraparticle diffusion and Elovich kinetic models were applied to the experimental data in order to describe the removal mechanism of dye ions by waste marble dust. The pseudo-second order kinetic was the best fit kinetic model for the experimental data. Thermodynamics parameters such as Δ<em>G</em>, Δ<em>H</em> and Δ<em>S </em>were also calculated for the adsorption processes. The experimental data were used to construct an artificial neural network (ANN) model to predict removal of malachite green and acid blue 161 dyes by waste marble dust. A three-layer ANN, an input layer with four neurons, a hidden layer with 12 neurons, and an output layer with one neuron is constructed. Different training algorithms were tested on the model to obtain the proper weights and bias values for ANN model. The results show that waste marble dust is an efficient sorbent for malachite green dye and ANN network, which is easy to implement and is able to model the batch experimental system.</p> </div> <p> </p>

Methylene Blue Removal from Aqueous Solution by Adsorption on Nitric Acid Modified Water Treatment Sludge

Nitric acid modified water treatment sludge (NS) was used as an adsorbent for methylene blue (MB) removal from aqueous solution in a batch experiment system. Surface area and pore volume were characterized by BET-N2 method. Zeta potential measurements of the NS showed a negatively charge which has the potential to attract positively charged molecules. The effect of initial MB concentration and initial pH solution were investigated. When the initial MB concentration was increased, the percentage of MB removal decreased accordingly while the amount of adsorbed MB on NS at equilibrium time (qe) increased. For the effect of initial pH solution, the adsorption of MB was increased with increase in pH. The maximum removal was observed at pH 11. The result indicates that NS can be used as low cost adsorbent in wastewater treatment for cationic dye removal.

Characterization of Durian Seed Starch/PVOH Composite Hydrogel as a Potential Adsorbent for Removal of Hazardous Dyes

The intention of this study was to prepare the environment friendly durian seed starch/polyvinyl alcohol (DSS/PVOH) composite hydrogels modified by chemical cross-linking with glutaraldehyde and to assess the adsorption potential of the DSS/PVOH composite hydrogels for the removal of the synthetic dyes from aqueous solution. The hydrogels were characterized by swelling behavior and scanning electron microscope (SEM). The effect of DSS content and initial dye solution pH on the adsorption capacity was studied conducting batch experiment system. The DSS/PVOH composite hydrogels consisting 3% DSS has optimum adsorption capacity of 3.411 mg/g (for methylene blue under the condition of pH 7) and 3.274 mg/g (for acid orange 8 under the condition of pH 2.5) at 24 h of contact time. The adsorptions were well fitted by the pseudo-second order kinetic model. It was indicated that the mechanism of removal predominant is effective for low dye concentrations, below 10 mg/l.

KINETIC AND ISOTHERM STUDY OF CUPPER ADSORPTION FROM AQUEOUS SOLUTION USING WASTE EGGSHELL

The sorption of Cu2+ ions from aqueous solutions by eggshell was investigated in a batch experimental system with respect to the temperature, initial Cu2+ concentrations, pH, and biosorbent doses. The adsorption equilibrium was well described by the Langmuir isotherm model with the maximum adsorption capacity of 5.05 mg Cu2+/g eggshell at 25 °C. The value of qe increased with increasing the temperature while also increases the release of Ca2+ and HCO−3 ions from the eggshell. The highest sorption of Cu onto the waste eggshell was determined at the initial pH value of 4.0. The results confirming that the adsorption reaction of Cu2+ on the eggshell was thought to be endothermic. A comparison of the kinetic models such as pseudo first and second-order kinetics, intraparticle diffusion, and Elovich on the sorption rate demonstrated that the system was best described by the pseudo second-order kinetic model.

Influence of the Inoculation Volume on Methanogenesis by Thermophilic Anaerobic Digestion with Residue from Hydrogen Production Fermentation Using Combined Substrate of Sludge and Food Waste

This paper investigated the influence of the inoculation volume of dewatering sludge on thermophilic anaerobic digestion in residue of fermentative hydrogen production using combined sludge and food waste in batch experimental systems. The inoculum to residue ratios were 10%, 30%, 50%, 70%, 90%, respectively. The results showed that the biogas production increased with the inoculation volume except for 90%,and the optimum inoculation volume was 70%.

The use of NARX neural network for modeling of adsorption of zinc ions using activated almond shell as a potential biosorbent

In this study, nonlinear autoregressive model processes with exogenous input (NARX) are applied for the prediction of percentage adsorption efficiency for the removal of zinc ions from wastewater by activated almond shell. The effect of operational parameters such as pH, dosage, particle size and initial metal ions concentration are studied to optimize the conditions for maximum removal of zinc ions. The model is first developed using a two layer NARX network. A comparison between the model results and experimental data showed that the NARX model is able to predict the removal of zinc ions from wastewater. The outcomes of suggested NARX modeling were then compared to batch experimental studies. The results show that activated almond shell is an efficient sorbent and NARX network, which is easy to implement and is able to model the batch experimental system.

Optimizing copper ions removal from industrial leachate by explored vermiculite—A comparative analysis

In this work, the sorbent behavior of vermiculite to remove copper from industrial leachate was studied in batch experimental system. The effect of initial pH (3, 6, and 8), adsorbent dosage (2, 6, and 10g/L), and contact time (5, 20, and 60min) on the removal of heavy metals was investigated. At first stage, one-factor-at-a-time experiments were performed to see the individual effects of initial pH, adsorbent dosage, and contact time. The statistical solutions are implemented to decide which one of them is most suitable for adsorption studies. To study the two factor interactions, response surface modeling (RSM) based on Box–Behnken (BB) approach, factorial D-optimal design and Taguchi methods are. The adsorption kinetic models were also tested for the validity. The second order model with the high correlation coefficients best described adsorption kinetic data. Lagergreen first order, Elovich, and the pseudo-second order kinetic model are employed to optimized levels of the analyzed factors. Finally, the removal of Cu(II) using vermiculite reached at 96.87%, at the optimum level of 8 initial pH, 10g/L of adsorbent dosage, and 10min of contact time. Taguchi design was found to be appropriate on account of time-consuming and cost-effectiveness.

Chelating Agent EDDS in Removal of Copper (II) with Three Adsorption Materials

Recently, chelating agents have been widely applied to remove heavy metals for their highly effective capacities. In this study, three kinds of adsorption materials, 719 strongly basic anion exchange resin, γ-Al2O3 and activated carbon, were investigated to remove copper(II) under the existence of chelating agent EDDS. Adsorption isotherm and kinetics of copper(II) were assessed in batch experimental systems, pH and initial concentrations were also conducted to evaluate the effects on copper(II) removal. Results indicated the adsorption capacity with three absorbents was enhanced from 0.62, 7.26, 6.73 mg/g to 17.21, 24.68, 24.90 mg/g respectively when the chelating agent EDDS existing in aquatic phase. The experimental isotherms are fitted to Langmuir and Freundlich models, results show that 719 strongly basic anion exchange resin and γ-Al2O3 have good correlation coefficients obtained from Langmuir model, and activated carbon is better to fit the Freundlich model.

The Design and Implementation of Adsorptive Removal of Cu(II) from Leachate Using ANFIS

Clinoptilolite was investigated for the removal of Cu(II) ions from industrial leachate. Adaptive neural fuzzy interface system (ANFIS) was used for modeling the batch experimental system and predicting the optimal input values, that is, initial pH, adsorbent dosage, and contact time. Experiments were studied under laboratory batch and fixed bed conditions. The outcomes of suggested ANFIS modeling were then compared to a full factorial experimental design (23), which was utilized to assess the effect of three factors on the adsorption of Cu(II) ions in aqueous leachate of industrial waste. It was observed that the optimized parameters are almost close to each other. The highest removal efficiency was found as about 93.65% at pH 6, adsorbent dosage 11.4 g/L, and contact time 33 min for batch conditions of 23 experimental design and about 90.43% at pH 5, adsorbent dosage 15 g/L and contact time 35 min for batch conditions of ANFIS. The results show that clinoptilolite is an efficient sorbent and ANFIS, which is easy to implement and is able to model the batch experimental system.

폴리프로필렌 수지 이용 연료유 생성을 위한 열분해 반응에서 제올라이트계 촉매의 영향

폐 플라스틱을 이용한 연료유 생산 공정을 위한 폴리프로필렌(PP) 수지에 대한 열분해 반응 실험을 하였다. 질소 분위기에서 상온에서 <TEX>$650^{\circ}C$</TEX> 까지의 비등온 조건에서의 열분석기와 <TEX>$420^{\circ}C$</TEX> 등온에서의 Pyrolyser GC-mass 분석기, <TEX>$420^{\circ}C$</TEX>의 배치형 반응기에서 무촉매반응과 천연제올라이트, 폐 FCC 촉매, ZSM-5 등의 제올라이트 계 촉매를 사용한 열분해 실험이 행하여졌다. TGA 실험에서 PP 수지의 열분해반응은 <TEX>$330^{\circ}C$</TEX> 부근에서 시작되어, <TEX>$497^{\circ}C$</TEX>에서 완결되었다. 촉매반응에서 제올라이트 계열 촉매는 폐 FCC 촉매> 천연제올라이트> ZSM-5> PP의 순으로 열분해 반응속도를 높이는데 유효하였다. 열분해가 완료되는 온도도 폐 FCC 촉매 첨가 시 가장 낮게 나타났다. PY-G.C. mass 실험에서 PP 수지 만의 경우에서보다 촉매가 첨가됨에 따라 탄소 수가 낮은 생성물이 생성되는 것을 알 수 있었다. ZSM-5 촉매나 폐 FCC 촉매 첨가 시 특히 낮은 탄소 수의 생성물이 많이 생성되었다. 회분식 반응기에서 초기 오일생성율은 폐 FCC 촉매 첨가시 가장 높지만, 최종 오일전환율은 천연제올라이트 첨가 시가 폐 FCC 촉매 첨가 시보다 2% 정도 높았다. 탄소분석에서도 폐 FCC 촉매 첨가가 경유 성분이 주성분으로 요구되는 연료유 제조에 우수 하였다. The effects of zeolite-type catalysts addition on the thermal decomposition of the PP resin have been studied in a thermal analyzer, a Pyrolyser GC-mass, and a small batch reactor. The zeolite type catalysts tested were natural zeolite, used FCC catalyst, and ZSM-5. As the results of TGA experiments, the pyrolysis starting temperature for PP varied in the range of <TEX>$330{\sim}360^{\circ}C$</TEX> according to the heating rate. Addition of the zeolite type catalysts in the PP resin increased the pyrolysis rate in the order of used FCC catalyst> natural zeolite> ZSM-5 > PP resin. Adding the used FCC catalyst in the PP reduced most effectively the pyrolysis finishing temperature. In the PY-G.C. mass experiments, addition of zeolite type catalysts decreased the molecular weight of pyrolyzed product. In the batch system experiments, the mixing of used FCC catalyst enhanced best the initial yield of fuel oil, but the final yield of fuel oil was 2% higher in the case of mixing of natural zeolite. Also in the carbon number analysis, used FCC catalyst was the most useful one in this experiments for fuel oil.

The Removal of Hg (II) Ions from Laboratory Wastewater onto Phosphorylated Haloxylon ammodendron: Kinetic and Equilibrium Studies

Haloxylon ammodendron (HA), a desert plant residue, has been utilized as adsorbent material for the removal of Hg (II) ions from laboratory wastewater after treatment with phosphoric acid to form Haloxylon ammodendron cellulose phosphate (HACP). Three levels of HACP having different phosphorous content were prepared. The HACP samples were characterized by estimating the phosphorous content as well as FT-IR spectra. Using the batch experimental systems, the removal of Hg (II) on the HACP particles was investigated. The data of the adsorption isotherm was tested by the Langmuir, Freundlich and Temkin models. The removal processes of Hg (II) onto HACP particles could be well described by pseudo-second order model. The adsorption rate of mercury was affected by the initial heavy metal concentration, initial pH, adsorbent dose and agitation time and temperature as well as extent of modification. The adsorption experiments indicated that the HACP particles have great potential for the removal of Hg (II) from laboratory wastewater. The maximum adsorption capacity (Qmax) of the HACP towards Hg (II) ions was found to be 384.6 and 416.7 and 476.2 mg/g at 30, 40 and 50°C, respectively. Similarly, the Freundlich constant, n values were found to be 6.6, 4.4 and 3.8 at 30, 40 and 50°C, respectively. The thermodynamics constants of the adsorption process: ΔH°, ΔS° and ΔG° were evaluated.

Comparison of different physico-chemical methods for the removal of toxicants from landfill leachate

Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT=1.9 days) removed 46-78% of COD and 96-73% of NH(4)(+)-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD(5)/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0gL(-1)) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH(4)(+)-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr>Zn>Cd>Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe(2+):H(2)O(2)=1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity.

Removal of basic dye (basic magenta) using low-cost biosorbents from aqueous solutions: kinetic and equilibrium studies

The removal of basic magenta dye by low-cost biosorbents has been investigated using the batch experimental system. The adsorption of basic magenta onto various adsorbents was solution pH-dependent and the maximum removal occurred at basic pH (ca. 10.0). The kinetic experimental data were analysed using the Lagergren pseudo-first-order equation and pseudo-second-order equation equations to examine the mechanism of adsorption, and the results suggested that the adsorption of basic magenta onto various adsorbents was best represented by the pseudo-second-order equation. The linearised Langmuir and Freundlich adsorption isotherms were used to fit the equilibrium data and the adsorption isotherms for various adsorbents at all different temperatures exhibited Freundlich behaviour.

Adsorption potential of mercury(II) from aqueous solutions onto Romanian peat moss

This study was undertaken to evaluate the adsorption potential of Romanian peat moss for the removal of mercury(II) from aqueous solutions. The batch system experiments carried out showed that this natural material was effective in removing mercury(II). The analysis of FT-IR spectra indicated that the mechanism involved in the adsorption can be mainly attributed to the binding of mercury(II) with the carboxylic groups of Romanian peat moss. Adsorption equilibrium approached within 60 min. The adsorption data fitted well the Langmuir isotherm model. The maximum adsorption capacity (qmax) was 98.94 mg g−1. Pseudo–second-order kinetic model was applicable to the adsorption data. The thermodynamic parameters indicate that the adsorption process was spontaneous as the Gibbs free energy values were found to be negative (between −17.58 and −27.25 kJ mol−1) at the temperature range of 6–54°C.

Comparison of Basic Dye Crystal Violet Removal from Aqueous Solution by Low-Cost Biosorbents

The removal of basic dye crystal violet by low-cost biosorbents was investigated in this study using a batch experimental system. The adsorption of crystal violet onto various adsorbents was solution pH-dependent and the maximum removal occurred at basic pH 10.0. The kinetic experimental data were analyzed using pseudo-first-order and pseudo-second-order equations to examine the adsorption mechanism and the intraparticle diffusion model to identify the potential rate controlling step. These results suggested that the adsorption of crystal violet onto various adsorbents was best represented by the pseudo-second-order equation. The suitability of the Langmuir and Freundich adsorption isotherms to the equilibrium data was also investigated at various temperatures for all four sorbents and the adsorption isotherms exhibited Freundlich behavior. The Freundlich constant Kf was 1.55 for alligator weed, 2.33 for Laminaria japonica, 9.59 for rice bran and 5.38 (mg/g)/(mg/L)1/n for wheat bran, respectively at adsorbent concentration 5 g/L, pH 10.0 and 20°C. The thermodynamic parameters (ΔH, ΔG, and ΔS) were calculated and the results showed that the adsorption process for various adsorbents was spontaneous, endothermic, with an increased randomness, respectively. The particle size and the reaction temperature exhibited an insignificant impact on the adsorption equilibrium of crystal violet. The adsorbents investigated could serve as low-cost adsorbents for removing the crystal violet from aqueous solution.

Performance of vegetated and non-vegetated vertical flow reed beds in the treatment of diluted leachate

This study was undertaken to investigate the behaviour of a vertical flow reed bed system with 3 kind of wastewaters (W1, W2 and W3) and for two hydraulic retention times (3 and 7 days) as well as to assess the role of Phragmites Australis in constructed wetland treatment processes. The adopted batch experimental system consisted of six vertical flow filters, filled with granular media and planted with reeds. For each vegetated reactor there was a correspondent blank in order to make a comparison. Wastewaters were obtained mixing tap water, MSW landfill leachate and activated sludge in different percentages. W1, W2 and W3 were designed in order to reproduce treated or untreated wastewaters not in compliance with legislation in force (Directive 91/271/EEC), with increasing level of NH4 +-N from W1 (16.3 mg/L) to W3 (76.0 mg/L). In average terms, 3 days was sufficient for W1 and W2 to face the compliance limits; while, for W3 even 7 days was not sufficient to respect the compliance limit for ammonia nitrogen (1.4 times greater). The obtained results shown that the vegetation played an essential role especially in the removal of nitrogen: for the wastewater with the highest loads the contribution of reeds in the removal of nitrogen was greater than that of biofiltration processes. The contribution of the vegetation was also detectable in the removal of orthophosphate, but with minus efficiency.

Effect of Bacillus subtilis on granite weathering: A laboratory experiment

We performed a comparative experiment to investigate: (1) how the ubiquitous soil bacterium Bacillus subtilis weathers granite; and (2) which granite-forming minerals weather more rapidly via biological processes. Batch system experiments (granite specimen in a 500 ml solution including NaCl, glucose, yeast extract and bacteria B. subtilis at 27 °C) were carried out for 30 days. Granite surfaces were observed by SEM before and after the experiment. B. subtilis had a strong influence on granite weathering by forming pits. There were 2.4 times as many pits and micropores were 2.3 times wider in granite exposed to B. subtilis when compared with bacteria-free samples. B. subtilis appear to preferentially select an optimum place to adhere to the mineral and dissolve essential elements from the mineral to live. Plagioclase was more vulnerable to bacterial weathering than biotite among the granite composing minerals.