ADSORPTION CHARACTERISTICS OF MANGO LEAF (Mangifera indica) POWDER AS ADSORBENT FOR MALACHITE GREEN DYE REMOVAL FROM AQUEOUS SOLUTION

The adsorption of malachite green (MG) dye on mango leaf powder (MLP) was investigated in a batch process. The adsorbent prepared was characterized by Fourier Transform Infrared Spectroscopy. Operational parameters such as initial dye concentration, contact time and solution temperature governing the adsorption process were studied and evaluated. Equilibrium data were fitted to both Langmuir and Freundlich isotherm models, Langmuir model gave the best fit. The maximum monolayer coverage Q0 was 4.49 mg/g. Kinetic parameters, rate constants, equilibrium sorption capacities, and related correlation coefficients of pseudo-first-order and pseudo-second-order models were calculated and discussed; the pseudo second-order model provided the best correlation with R2 ≥ 0.99. Thermodynamic functions such as Standard free energy (ΔG0), standard enthalpy (ΔH0), and standard entropy (ΔS0) were also calculated. The adsorption process was found to be feasible, spontaneous and endothermic in nature.Keywords: Mango leaf powder, Malachite green, Equilibrium, Adsorption, Thermodynamic

Optimization and inhibitive effects of Sweet Potato Leaf Extract (SPLE) on mild steel

Weight loss and electrochemical techniques were used to evaluate the inhibition efficiency of sweet potato leaf extracts (SPLE) as inhibitor on mild steel in phosphoric acid. Box Behnken design was used to examine the interactions of these variables: acid concentration (0.5–1.5 M); time (5–10 days); inhibitor concentrations (0.3–0.9 g/L) and temperature (30–60 °C) respectively. Polarization and Electrochemical impedance and were used to measure the inhibition efficiency. The surface morphology of coupons was analysed using Scanning Electron Microscope (SEM). The experimental data was statistically analysed and regression equation was generated for inhibition efficiency. The weight loss measurement revealed that extract acts as an inhibitor for mild steel in phosphoric acid and decreases rate of corrosion. The results of inhibition efficiency derived from polarization studies and impedance analyses agree. The validated experiment's coupon created a better protected inhibitive layer than coupon of the best process level as observed from experimental design, according to SEM analysis. It can be concluded that the extract operated as an inhibitor by producing outer film on the surface of mild steel

Trapping synthetic dye molecules using modified lemon grass adsorbent

Please read abstract in the article.Universiti Sains Malaysia, LAUTECH 2016 TET Fund Institution Based Research Intervention and the TWAS-NRF.https://www.tandfonline.com/loi/ldis20hj2023Chemistr

Preparation and Characterization of Modified Adsorbents Derived from Pawpaw (Carica papaya) Leaf

The feasibility of a new and novel adsorbent was investigated by impregnation of pawpaw leaf (Carica papaya) in H2SO4 and NaOH respectively. The adsorbents prepared were characterized using FTIR, SEM, TGA and EDX techniques respectively. Physicochemical parameters of these adsorbents such as pH, moisture content, ash content, porosity and iodine number were also carried out; the results were then compared with the expensive commercial activated carbon (CAC) parameters. A close agreement in moisture, pH, porosity, ash content and iodine number of the acid activated pawpaw leaf (Carica papaya) shows its feasibility as a good and effective adsorbent. Conclusively, the present investigation shows that acid activated C. papaya leaf is a good and viable alternative adsorbent, which could be used in lieu of expensive CAC for adsorption processes

Functionalized locust bean pod (Parkia biglobosa) activated carbon for Rhodamine B dye removal

Activated carbon prepared from locust bean husk was modified using ortho-phosphoric acid (ALBP) and used to scavenge Rhodamine B (RhB) dye from aqueous solutions. Characteristic features of the adsorbents were investigated using SEM, FTIR, pHpzc and Boehm Titration (BT) techniques respectively. Batch studies were used to determine the influences of contact time, temperature and initial Rh–B dye concentrations. Adsorption data were analysed using four different isotherm models. The maximum monolayer adsorption capacity of 1111.1 mgg-1 was obtained for RhB dye adsorption. The kinetics of the adsorption process was studied using pseudo-first-order, pseudo-second-order Elovich and intraparticle diffusion models respectively. The experimental data was best described by pseudo-second-order kinetic model. Favourability of the process of adsorption was also established by the separator factor (RL) value ranging from 0 and 1, while the mean energy of adsorption (Ea) was 1.12 kJmol- 1 suggesting that the removal of Rh–B dye from aqueous solution followed a physisorption process. For the thermodynamic investigations, the positive values of ΔS (280.956 Jmol 1K 1) indicates the affinity of adsorbent for the Rh–B dye uptake and increase randomness at the solid–solution interface during adsorption of Rh–B dye onto the surface of the active sites of ALBP. The negative value of ΔG (-31.892 to -26.355 kJmol-1) depicts the spontaneity and feasibility of the adsorption process. The cost analysis provides a simple proof that ALBP (42.52 USD per kg) is approximately six times cheaper than Commercial Activated Carbon, CAC (259.5 USD per kg). The present study therefore established the suitability of ALBP for effective removal of Rh–B dye from aqueous solutions.This work was supported by The World Academy of Science (TWAS) in form of Research grants; Research Grant number: 11–249 RG/CHE/ AF/AC_1_UNESCO FR: 3240262674 (2012), 15–181 RG/CHE/AF/AC_1_: 3240287083 (2015) for the purchase of Research Equipments. NRFTWAS for Doctoral Fellowship award given to the second author (UID:105453 & Reference: SFH160618172220) and LAUTECH 2016 TET Fund Institution Based Research Intervention (TETFUND/DESS/UNI/ OGBOMOSO/RP/VOL. IX) respectively.https://www.heliyon.comam2020Chemistr

Environmental Applications of Metal−Organic Frameworks and Derivatives: Recent Advances and Challenges

The consequence of environmental pollution has raised the dire need for the discovery of efficient and potent methods for detection and removal of pollutants released into air and water bodies. Metal-organic frameworks (MOFs) are porous coordination polymers having intriguing features such as large surface areas, tailorable pore size and highly dense active sites reported for various environmental applications. Recent developments have focused on the modification of MOF structures, development of MOF-based materials including functionalized MOFs, MOF composites/hybrids and MOF derivatives. These modifications confer new and desirable properties over pristine MOFs and consequently lead to enhanced efficiency for pollutant sensing and adsorption applications. This chapter focuses on the recent developments and challenges in the use of MOF-based materials for sensing and adsorption of pollutants from air and water in the past seven years. Some challenges and future prospects are also discussed. In spite of the challenges encountered with the use of MOF-based materials for detection and removal of gaseous and water pollutants, they remain valuable materials for environmental applications

Photocatalytic Conversion of CO2 Using ZnO Semiconductor by Hydrothermal Method

Photocatalytic conversion of CO2 using ZnO semiconductor is an effective, simple, economical and attractive way of combating energy problems resulting from anthropogenic emissions of CO2 i.e. greenhouse gases to the atmosphere. This article focuses on current advances in CO2 photoreduction by hydrothermal method. The fundamental photocatalytic CO2 reduction system by photocatalysts especially ZnO has been explicated. The synthetic protocol of ZnO and its growth mechanism in alkaline solution is elaborated with specific illustration of defect chemistry and its influence on CO2 reduction activity and selectivity. Conclusively, brief challenges of its current state and future prospects were also discusse