The diminishing supply of fossil fuels, their detrimental environmental effects, and the challenges associated with the disposal of agro-waste necessitated the development of renewable and sustainable alternative energy sources. This study aims at developing bio-briquettes from
The quest for an efficient and sustainable adsorbent material that can effectively remove harmful and hazardous dyes from industrial effluent has become more intense. Thermally modified nanocrystalline snail shell is a new biosorbent for removing methylene blue dye from contaminated wastewater.
The use of acid-modified mango pod (AMMP) sorbent for removing Rhodamine B (Rh-B) dye from aqueous media was investigated. Raw mango pod (RMP) and AMMP sorbents were characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), powdered X-ray diffractogram (PXRD), Fourier transform infrared (FTIR), point of zero charge pH (pHpzc ), and Boehm titration (BT) techniques. Batch adsorption was employed to examine the influence of operational factors. Sorption kinetic parameters were calculated using pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The pseudo-second-order model best fitted the adsorption kinetic data most with maximum correlation coefficient (R2 > 0.99). The process of the adsorption was controlled by both boundary layer and intraparticle diffusion mechanisms. Four isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin) were utilized to analyze the equilibrium data at various temperatures. Freundlich model gave the best fit with the maximum regression (0.99), while the Langmuir isotherm model established a maximum monolayer adsorption capacity of 500 mg g-1 . Thermodynamic parameters studied revealed that the interaction is spontaneous and endothermic in nature. The cost analysis of the current study provides convincing proof that AMMP is efficient for removing Rh-B dye from solution by providing a saving of 225.2 USD/kg, which is eight times cheaper than commercial activated carbon. Consequently, the study revealed that AMMP is a viable, effective, and sustainable sorbent for Rhodamine B dye removal. PRACTITIONER POINTS: The powdered X-ray diffractogram (PXRD) showed the formation of new and intense peaks with the presence of highly organized crystalline structures on acid-modified mango pod (AMMP). Surface morphology of AMMP showed well-developed open surface pores required for effective adsorption of Rh B dye molecules. Economic feasibility of the present study showed that AMMP is more affordable than commercial activated carbon that costs USD 259.5/kg, thus translated to a saving cost of USD 225.2/kg and more than 7.5 times cheaper than the commercial activated carbon (CAC).
Co-electrolysis of formic acid and water using an indium oxide cathode catalyst yields a mixture of methanol, ethanol and iso-propanol with a Faraday efficiency up to 82.4%. The reaction of aqueous carbon dioxide occursviaa competing pathway.
The undeniable emission of anthropogenic greenhouse gases into the atmosphere remain a foremost cause of global climate changes threatening global peace [1-3] . A number of thermal catalysts are available that can convert carbon dioxide (CO 2 ) to methanol with reasonable yield and selectivity at significantly elevated temperature and pressure, using gaseous molecular hydrogen. Hydrogen has to be produced first in a separate, preceding step via water electrolysis. However, renewable energy is available primarily in the form of electrical power. Currently, the available catalysts for electrochemical reduction of CO 2 stop at CO or formic acid as the reduction products. At present, the copper is the only catalyst that can convert CO 2 to products beyond CO or formic acid to higher order alcohols. In this study, we have developed a metal oxide catalyst that is capable of converting formic acid to C 1 , C 2 and C 3 alcohols at an overall efficiency of >60%. The electrochemical characteristics were thus examined via linear sweep voltammetry and chronoamperometric (CA) methods. The formic acid reduction reaction result revealed a current density of 62 mA/cm 2 at 2.4 V with ohmic resistance of 5.8 Ωcm 2 . The Tafel slope was also used to evaluate the rate-determining step for the electrochemical reaction of formic acid reduction reaction which is 580 mV/dec. Tafel values of 40 cycles were consistent with each other and with the bulk metal, therefore it can be concluded that there were perhaps no significant changes in the mechanism of reduction. However, the chronoamperometry result at 2.4 V showed the current density of 33 mA/cm 2 ; during which methanol, ethanol and isopropanol were detected as products of formic acid reduction reactions (Fig. 1). First experiment with CO 2 electroreduction was also conducted, the findings and the reliance of the study shall be presented. This study therefore successfully developed and converted a thermal metal oxide catalyst to an electrocatalyst that could do the conversion of formic acid and CO 2 near room temperature and with water as a source of hydrogen. [1] C. F. Shih, T. Zhang, J. Li, C. Bai, Joule 2018 , 2 , 1925. [2] O. Martin, A. J. Martín, C. Mondelli, S. Mitchell, T. F. Segawa, R. Hauert, C. Drouilly, D. Curulla-Ferré, J. Pérez-Ramírez, Angew. Chemie Int. Ed. 2016 , 55 , 6261. [3] L. Wang, Y. Yi, H. Guo, X. Tu, ACS Catal. 2018 , 8 , 90. Figure 1
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