Contentslistsavailableat ScienceDirect AppliedSurfaceScience journal homepage: www.elsevier.com/locate/apsusc ExperimentalandDFTinvestigationofceria-nanocompositedecoratedAC derivedfromgroundnutshellforefcientremovalofmethylene-bluefrom wastewater efuent Muntathir Alshabib a ,MusaAzeezOluwadamilare b ,AbdulkadirTanimu b ,IsmailAbdulazeez b , Khalid Alhooshani b ,SaheedA.Ganiyu b, ⁎ a Chemical Engineering, King Fahd University of Petroleum & Minerals, P.O. Box 31261, Dhahran, Saudi Arabia b Chemistry Department, King Fahd University of Petroleum & Minerals, P.O. Box 31261, Dhahran, Saudi Arabia ARTICLEINFO Keywords: GroundnutshellAC-derived Nano-ceria Methyleneblue Adsorption DFT-calculation ABSTRACT Removalofdyesisasignifcantaspectofenvironmentalremediationtoensurecleanwaterandatmosphere.In thisstudy,wereportanincorporationofnanoceriaatdiferentweightloadingsviasolidstateimpregnationon the highly porous activated carbon (AC) derived from groundnut shell to form nano-ceria decorated AC for efectiveremovalofcationicdye(methyleneblue).TheadsorptioncapacityofMBwithinashortperiodishighly remarkablewith199.76mg/g,correspondingto99.9%efciencyin400ppmusing40mgweightadsorbent. The adsorbent at relatively low loadings (0.5–1%) of nano-ceria of AC favors signifcantly adsorption ofMB, owing to the high degree of dispersion of cerium with improved textural properties, acidity and surface chemistry. The adsorbents were characterized by the N 2 -sorption, spectroscopies; (XRD, FTIR and Raman), microscopies (SEM and TEM) and temperature programmed desorption (TPD) techniques. The isotherm and kineticsinformationrevealsthattheadsorptionmechanismofMBiselucidatedbytheLangmuirandpseudo- secondordermodels,respectively.QuantumchemicalDFTcalculationsrevealedthatceriaincorporationlowers theHOMO-LUMOenergygap(ΔE),increasesthechemicalsoftnessandenhancestheadsorptioncapacityofAC withatheoreticaladsorptionenergyof−18.5kcal/mol. 1. Introduction Methylene blue (MB), which belongs to the class of basic/cationic dyes [1], is extensively utilized for both industrial and non-industrial purposes [2–8].However,despiteitsimportantapplications,therelease of MB to the environment might lead to the contamination of water bodies [9]. Owing to its simplicity and efectiveness, adsorption has beenlongthepreferredtreatmentmethodtoeradicateawiderangeof pollutants including MB from wastewaters [10].Thankstotheirgreat adsorption capacity, excellent chemical stability, and robust mechan- ical rigidity, activated carbons (AC) remain to be the most common adsorbentsforwastewatertreatment [11].However,theproductionof ACs, particularly in a large scale, is plagued by the high cost of pre- cursors [12].Accordingly,researchershavebeenattractedbytheuseof agricultural wastes such as rice straws [13,14], bamboos [15,16],co- conut shells [17,18], and date pits [19,20] as cheap and eco-friendly startingmaterialsforthepreparationofACs. Groundnutsareoneofthemostwidelyproducedcropsintheglobe astheycontainbioactiveandnutritiouscomponentsthatarebenefcial forhumanhealth [21].However,withtheincreasingrateofgroundnut productionworldwide,appreciableamountsofhusksaregeneratedas leftoverwastes.Groundnutshellsareregardedasabundantagricultural wastes, which are produced after the elimination of groundnut kernel from its husk [22]. As reported, such a type of wastes undergoes a sluggishdegradationrate,andmostofthemarebeingdisposedoffrom the environment by either incineration or land dumping, thereby creating more severe pollution issues [22,23]. With a view to mini- mizing the environmental footprints, groundnut husks can be efec- tively utilized for several applications [22]. One of the approaches is theconversionoftheseagro-wastesintoACsasasustainableresource of producing adsorbents. Previous investigations have proven the ap- titude of groundnut shells-derived ACs for the removal of several pol- lutantsfromwastewaters [24–26]. However,ithasbeenreportedthatmodifyingthesurfaceofACsby metaloxidesrendersthemmoreefective fortheremovalofpollutants includingdyes [27,28].Inthisregard,Kamarajet.al [29] haveshown https://doi.org/10.1016/j.apsusc.2020.147749 Received3July2020;Receivedinrevisedform30August2020;Accepted30August2020 ⁎ Correspondingauthor. E-mail address: gsadewale@kfupm.edu.sa (S.A.Ganiyu). Applied Surface Science 536 (2021) 147749 Available online 05 September 2020 0169-4332/ © 2020 Elsevier B.V. All rights reserved. T