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The paper assesses batch system microcrystalline cellulose (MCC) adsorptive ability for copper and iron uptake from aquatic environment. Field emission scanning electron microscope (FESEM), point zero charge and Fourier transform infrared (FTIR) spectroscopy were used to examine the physicochemical and morphological features of MCC. The batch system of the sequestration progression for the elimination of Cu(II) and Fe(II) was used by varying the solution pH, MCC doses, initial copper and iron concentration, and resident time. The maximum removal percentage for Cu(II) and Fe(II) were 99.5% and 96.4%, respectively, at pH 7. The influence of MCC dosage showed the 1.0 g/L of adsorbents results the highest percentage of Cu(II) (99.8%) and Fe(II) (88.63%) correspondingly. Equilibrium data for both metals were well fitted with both Langmuir and Freundlich isotherms, representing monolayer and multilayer adsorption systems. The maximum sorption capacity of MCC was 534.61 mg/g and 845.75 mg/g, respectively, for Cu(II) and Fe(II) ions at room temperature. Pseudo-second-order model best describes the copper and iron kinetic data, signifying the dominance of chemisorption adsorption relation between the negatively charged MCC and adsorbates. After four successive regeneration cycles, the MCC polymer maintained its maximal adsorption capacity, demonstrating effective copper and iron ion separation from aqueous solution. According to the study’s findings, poisonous heavy metals can be successfully removed from aquatic environments using eco-friendly microcrystalline cellulose.

African palm (Elaeis Guineensis) husk, an industries waste disposed of into drains and landfills can be source of precursor for the preparation of activated carbon. In this work, activated carbon was chemically prepared with H3PO4and modified with trisodium citrate. Evaluation of surface area and porosity and functionality were performed by nitrogen adsorption and FTIR techniques. The activated carbon was used in treating wastewater that contains Zn(II) by varying adsorbent dosage, sorption time, and pH. The adsorption capacity increased with increase in pH reaching a maximum at pH 6. Kinetic and isotherm studies of the new adsorbent (AC/Na-Ci) revealed that adsorption behavior follows Pseudo-second order reaction and Langmuir model respectively, with a maximum monolayer capacity of 131.58 mg/g. The removal efficiency of AC/Na-Ci in the treatment of wastewater containing Zn(II) was promising compared with other adsorbents, and it could be an nascent step towards achieving sustainable and environmentally friendly remediation.

The presence of cadmium ions in the environment is dangerous to a human being because of its chronic and acute health syndromes such as hypertension, testicular atrophy, and skeletal fetus malformation. To eliminate cadmium ions from the environment, cheap, non-toxic, and environmental-friendly biosorbents, an alkaline impregnated adsorbent, were prepared in this study. Alkaline impregnated chicken feather biosorbents (AICFB) were synthesized and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis. The AICFB prepared was employed for the cadmium sequestration from simulated wastewater. AICFB quantity, cadmium ion concentration, and temperature are parameters with significant effects on the metal ion sequestration process. Models by Langmuir, Freundlich, and Redlich-Peterson were assigned to analyse the adsorption isotherms. Experimental data seem good with all tested models, and best with the Redlich-Peterson model. The maximum sorption capacity of AICFB toward cadmium ion was 122.07 mg/g as monolayer entrapment at pH 6.5, 0.1 g of AICFB, 120 minutes contact time, and 298 K. The linear pseudo-first-order and pseudo-second-order kinetic models were applied for the analysis of kinetic data. The pseudo-second-order model suitably describes the cadmium ion uptake by AICFB, indicating the chemisorption process. The prepared AICFB demonstrates efficient cadmium metal sequestration from aqueous environments.

•Crude oil-contaminated soil bioaugmentation and biostimulation were studied.•Biostimulation was significant on the percentage of TPH biodegraded.•Degradation efficiency of 93.75% was obtained.•Model developed was effective for future prediction.•Bacteria isolates from native polluted site were effective for the process.

•Heavy metals removal from produced water using citrullus lanatuspeel.•Optimum removals were 76.31, 59.3, 69.91 and 84.08% for Pb2+, Zn2+, Fe2+and Cu2+.•Large surface area of 1249.7 m2/g was recorded.•Citrullus lanatuspeel acted effectively for heavy metals removal.

The study aims to develop an eco-friendly solution for addressing contaminants in hospital wastewater. To achieve this, banana peel, a cost-effective and easily available agricultural waste, was chemically modified using sulfuric acid and sodium hydroxide. The hospital wastewater was analyzed using an Atomic Absorption Spectrometer to identify the presence of heavy metals. The physicochemical properties were measured and compared against the standards set by the World Health Organization (WHO). Scanning electron microscopy and Fourier-transform infrared spectroscopy were used to characterize the chemically modified banana peel. Batch adsorption was conducted with the wastewater using the prepared adsorbent. The effect of contact time, mixing rate, temperature, and adsorbent dosage was examined to know the removal efficiency of the adsorbent. The experimental design incorporates Taguchi OA design to optimize the process. The total heavy metals discovered in the wastewater were As, Cd, Fe, Cu, Ni, Cr, Pb, Mn and Zn. The percentage of Cd, Fe, Cu, Ni, Cr and Pb removed were 79.5%, 87.9%, 56.9%, 89.0%, 88.5% and 93.5%, respectively, at temperature, adsorbent dosage, mixing rate and contact time of 30 °C, 3 g, 700 rpm and 60 min, respectively. The physicochemical properties remain within the acceptable WHO range except the turbidity. At optimum point, the percentage removal of Cd, Fe, Cu, Ni, Cr, Pb and Zn were 64.3%, 80.5%, 51.4%, 82.3%, 72.4%, 86.6% and 72.1%, respectively; while, the conductivity, pH, TDS, and turbidity value were, respectively, 20.57 mS/cm, 6.8, 10.16 mg/l, and 86.31 NTU. Characterization revealed the existence of active functional groups on the adsorbent surface enhancing the hospital wastewater treatment and change in its morphological structure after the treatment was noticed. In conclusion, the modified banana peel was effective for the treatment of hospital wastewater.

Poly(acrylonitrile-co-acrylic acid) was synthesized through redox polymerization reaction performed at 60°C under nitrogen gas by varying the feed ratio of acrylonitrile (AN) and acrylic acid (AA), and it was chemically modified with thiourea. The yield of polyacrylonitrile (PAN) and poly(AN-co-AA) samples were over 70%. The unmodified and modified samples were characterized using FTIR, SEM, CHNS, zeta potential and BET analysis. Fourier transform infrared (FTIR) spectrometer, scanning electron microscope (SEM) and Zetasizer characterized the morphology and structures of thiourea-modified poly(acrylonitrile-co-acrylic acid). Successful introduction of acrylic acid in copolymer was confirmed by the appearance of C=O at 1730 cm−1in its FTIR spectra. The polymer surface modification was accomplished by the total disappearance of C≡N band from FTIR analysis and the appearance of new peaks at 3351–3349 cm−1assigned to N–H2and OH groups, which confirmed successful incorporation of thiourea into prepared poly(AN-co-AA) chains. The average particle size of the prepared thiourea-modified poly(AN-co-AA) and poly(AN-co-AA), respectively, was 308 nm and 300 nm. CHNS elemental analysis revealed the percentage increments of carbon, hydrogen, nitrogen and sulfur components from unmodified to modified polymers. Zeta potential measurements were also inveterate the integration of thiourea, with modified poly(AN-co-AA) which was more negatively charged than the unmodified poly(AN-co-AA). The performance of adsorptive capacity of thiourea-modified poly(AN-co-AA) for cationic methylene blue and malachite green dyes as a case study revealed a better performance than that of poly(AN-co-AA) adsorbent. The results demonstrated that thiourea-modified poly(AN-co-AA) could be used as efficient adsorbents for cationic dye or pollutant removal from aqueous solution.

In this work, the control of the mole fraction of a fuel additive being produced in a reactive distillation column has been carried out using proportional-integral-derivative (PID) control. The fuel additive considered in this case was isopropyl alcohol, which was produced from the reaction between propylene and water. To accomplish the work, a ChemCAD model of the process was first developed and simulated to convergence before it was converted to dynamic type from which the dynamic responses of the system were generated and used, with the aid of MATLAB, to develop a transfer function model having the reboiler duty, the reflux ratio and the temperature of the bottom product as the input, the disturbance and the output variables of the process, respectively. The obtained transfer function model was used to develop the open-loop and the closed-loop Simulink models of the process that were also simulated. The closed-loop simulation was carried out with the objective of achieving a fuel additive product with a mole fraction of 0.97, and this was done using a PID controller that was applied inferentially via the product temperature. The results obtained showed that the control of the fuel additive mole fraction could be achieved inferentially, with PID controller tuned with Cohen-Coon and Simulink approaches, using product temperature.

The use of cheap and eco-friendly adsorbents studied as an alternative to activated carbon for removal of dyes from wastewater is the focus of this paper. Chitosan, which was produced from food industry waste (crab shells), was synthesized, characterized and utilized as adsorbent to remove cationic dye, basic blue, from wastewater by adsorption. Characteristics of the synthesized chitosan biosorbents was established using scanning electron microscope (SEM), and Fourier Transform Infra-Red (FTIR) spectroscopy. Experiments were conducted in batch forms to investigate the effects of contact time, initial dye concentration and adsorbent dosage. Kinetic and isotherm analysis of the adsorption process were also carried out. The results obtained revealed that removal efficiency of the chitosan was increased as the contact time and chitosan biosorbent dose were increased, but a decrease with increasing initial concentration of basic dye was observed. The pseudo-second order reaction model was found to describe the biosorption process best, with chemisorption as the rate limiting step. The maximum colour removal efficiencies of chitosan at dosage of 4 g for time duration of 90 min was found to be 91.88% of the dye from a solution of 80 ppm. The pseudo-second order kinetic model was also seen to agree very well with the dynamic behaviour of the adsorption of basic blue on chitosan under different contact time, initial dye concentrations and adsorbent dosages. The dynamic behaviour of adsorption of basic blue onto chitosan has the model fitness in the following order: pseudo-second order > Elovich model > pseudo-first order. The Elovich equation was found to be the best fit equilibrium isotherm for the sorption of basic blue onto chitosan based on linearized correlation coefficient. Moreover, the equilibrium isotherm has its model fitness to be in the order of Elovich model > Langmuir model > Freundlich model.

The quality of life on earth is directly linked to the overall quality of the environment. The natural ecosystem encompasses all living and non-living things existing on earth naturally. It is an environment that interacts with all living species, but which may be contaminated with diesel a derivative of hydrocarbons. Diesel spills contaminate both aquatic and terrestrial environments. To prevent the environmental and health risks of this, remediation needs to be advanced. Bioremediation, degradation by microbes, is one of the suitable methods for cleaning diesel contamination. In the present work, the biodegradation of diesel oil contaminated soil has been investigated comparatively with Pseudomonas aeruginosa and Pseudomonas fluorescence coupled with fertilizer as essential nutrients. Based on observations carried out in 18 days, Pseudomonas aeruginosa alone as well as in the presence of essential inorganic nutrients was found to exhibit higher remediation potential in degrading soil contaminated with diesel oil than Pseudomonas fluorescence.

This research work has been carried out to investigate the application of the Model Predictive Control Toolbox contained in MATLAB in controlling a reactive distillation process used for the production of a biodiesel, the model of which was obtained from the work of Giwa et al.1. The optimum values of the model predictive control parameters were obtained by running the mfile program written for the implementation of the control simulation varying the model predictive control parameters (control horizon and prediction horizon) and recording the corresponding integral squared error (ISE). Thereafter, using the obtain optimum value of 5 and 15 for control horizon and prediction horizon respectively as well as a manipulated variable rate weight of 0.025 and an output variable rate weight of 1.10, various steps were applied to the setpoint of the controlled variable and the responses plotted. The results given by the simulations carried out by varying the model predictive control parameters (control horizon and prediction horizon) for the control of the system revealed that optimizing the control parameters is better than arbitrary choosing. Also, the simulation of the developed model predictive control system of the process showed that its performance was better than those used to control the same process using a proportional-integral-derivative (PID) controller tuned with Cohen-Coon and Ziegler-Nichols techniques. It has, thus, been discovered that the Model Predictive Control Toolbox of MATLAB can be applied successfully to control a reactive distillation process in order to obtain better performance than that obtained from a PID controller tuned with Cohen-Coon and Ziegler-Nichols methods.

Reactive distillation is a process that combines chemical reaction and separation in a single piece of equipment (distillation column). The process has a lot of benefits especially for those reactions occurring at conditions suitable for the distillation of the process components, and these result in significant economic advantages. However, owing to the complexities resulting from the integration of reaction and separation, its control is still a challenge to process engineers because it requires a control method that is robust enough to handle its complexities. Therefore, in this work, model predictive control (MPC) has been applied to a reactive distillation process used for developing a renewable energy known as biodiesel. The control algorithm of the MPC was formulated with the aid of MPC toolbox of MATLAB/Simulink in which the closed-loop models of the process were developed and simulated. The analysis of the results obtained from the simulations carried out for the optimization of the tuning parameters revealed that, among the tuning parameters considered, integral absolute error of the control system was less affected by the control horizon because its p-value was greater than 0.05 based on 95% confidence level. Furthermore, the simulation of the closed-loop system of the process using model predictive control tuned with control horizon of 11, prediction horizon of 18, weight on manipulated variable rate of 0.05 and weight on output variable of 2.17, which were the optimum parameters obtained using Excel Solver, showed that the system was well handled by the controller under servo control because it was able to get settled at desired mole fractions within 60 min. However, the settling time recorded in the case of regulatory control system of the process with the same controller was found not to be encouraging. Therefore, it is recommended that further work should be carried out on this subject matter in an attempt to obtain tuning parameters that will make the settling time of the closed-loop system of the process under regulatory control simulation very reasonable.

The combination of chemical reaction and distillation, which is analogous to inserting a chemical reactor into a distillation column, is a phenomenon that can be accomplished using a single piece of equipment known as a reactive distillation column, and the phenomenon is, thereby, referred to as reactive distillation process. Because of this combination, a lot of benefits such as improving reaction conversion, suppressing side reactions and utilizing heat of reaction for mass transfer operation can be achieved. However, this combination has made the control of this process a little bit challenging because of some disturbances that normally affect its smooth running. Therefore, cascade control method, being a type that can be used to handle any disturbance before it affects the main process, is applied in this work to carry out the control of a biodiesel reactive distillation process using proportional-integral-derivative (PID) control algorithm. The responses of the process towards the applications of step changes to the input variable (reboiler duty) of the process revealed that it was stable because it could attain steady states. Also, the closed-loop simulations showed that cascade PID controller was better for the control of the process than the conventional PID controller owing to the fact that the responses of the cascade PID control system, upon the application of step changes to the set-point value of the controlled variable, were found to get to the desired setpoint faster and in a better way than those of the conventional PID control system. Moreover, the superiority of the cascade PID controller over the conventional one was demonstrated by the estimation of the integral absolute error (IAE) and integral squared error (ISE) of the cascade control system, which were obtained to be less than those of the conventional PID control system.

Thiourea-modified poly(acrylonitrile-co-acrylic acid) (TU-poly(AN-co-AA)) adsorbent was a surface modification of poly(acrylonitrile-co-acrylic acid) synthesized by facile redox polymerization. Surface functionalization with thiourea was carried out to provide hydrophilicity on the surface of a polymeric adsorbent. Fourier transform infrared (FTIR) spectrometer, scanning electron microscope (SEM), and Zetasizer characterized the morphology and structures of TU-poly(AN-co-AA). Copolymerization of poly(acrylonitrile-co-acrylic acid) and its successful incorporation of the thioamide group was confirmed by the FTIR spectra. The SEM micrographs depicted uniform and porous surface morphologies of polymeric particles. The average diameter of modified and unmodified poly(acrylonitrile-co-acrylic acid) was 289 nm and 279 nm, respectively. Zeta potentials of TU-poly(AN-co-AA) revealed the negatively charged surface of the prepared polymer. Adsorption capacities of hydrophilic TU-poly(AN-co-AA) were investigated using malachite green (MG) as an adsorbate by varying experimental conditions (pH, initial concentration, and temperature). Results showed that the pseudo-second-order reaction model best described the adsorption process with chemisorption being the rate-limiting step. Furthermore, Elovich and intraparticle diffusions play a significant role in adsorption kinetics. The equilibrium isotherm has its fitness in the following order: Freundlich model > Temkin model > Langmuir model. Thermodynamic analysis indicates that the sorption process is spontaneous and exothermic in nature. The reusability results suggested potential applications of the TU-poly(AN-co-AA) polymer in adsorption and separation of cationic malachite green dye from wastewater.