•Orange peel-derived hydrochars are obtained by hydrothermal carbonization.•New adsorbents are developed by thermal and chemical activation of the hydrochars.•Adsorption of emerging contaminants ...depends on the adsorbents’ characteristics.•Kinetic studies are performed and adsorption isotherms are determined and modeled.
Activated hydrochars obtained from the hydrothermal carbonization of orange peels (Citrus sinensis) followed by various thermochemical processing were assessed as adsorbents for emerging contaminants in water. Thermal activation under flows of CO2 or air as well as chemical activation with phosphoric acid were applied to the hydrochars. Their characteristics were analyzed and related to their ability to uptake three pharmaceuticals (diclofenac sodium, salicylic acid and flurbiprofen) considered as emerging contaminants. The hydrothermal carbonization and subsequent activations promoted substantial chemical transformations which affected the surface properties of the activated hydrochars; they exhibited specific surface areas ranging from 300 to ∼620m2/g. Morphological characterization showed the development of coral-like microspheres dominating the surface of most hydrochars. Their ability to adsorb the three pharmaceuticals selected was found largely dependent on whether the molecules were ionized or in their neutral form and on the porosity developed by the new adsorbents.
Unique zerovalent iron (Fe0) supported on biochar nanocomposite (Fe0-BRtP) was synthesized from Nephelium lappaceum (Rambutan) fruit peel waste and were applied for the simultaneous removal of 6 ...selected organochlorine pesticides (OCPs) from aqueous medium. During facile synthesis of Fe0-BRtP, Rambutan peel extract was used as the green reducing mediator to reduce Fe2+ to zerovalent iron (Fe0), instead of toxic sodium borohydride which were used for chemical synthesis. For comparison, chemically synthesized Fe0-BChe nanocomposite was also prepared in this work. Characterization study confirmed the successful synthesis and dispersion of Fe0 nanoparticles on biochar surface. Batch experiments revealed that Fe0-BRtP and Fe0-BChe nanocomposites combine the advantage of adsorption and dechlorination of OCPs in aqueous medium and up to 96–99% and 83–91% removal was obtained within 120 and 150 min, respectively at initial pH 4. Nevertheless, the reactivity of Fe0-BChe nanocomposite decreased 2 folds after being aged in air for one month, whilst Fe0-BRtP almost remained the same. Adsorption isotherm of OCPs were fitted well to Langmuir isotherm and then to Freundlich isotherm. The experimental kinetic data were fitted first to pseudo-second-order adsorption kinetic model and then to pseudo-first-order reduction kinetic model. The adsorption mechanism involves π-π electron-donor-acceptor interaction and adsorption is facilitated by the hydrophobic sorption and pore filling. After being reused five times, the removal efficiency of regenerated Fe0-BChe and Fe0-BRtP was 5–13% and 89–92%, respectively. The application of this Fe0-BRtP nanocomposite could represent a green and low-cost potential material for adsorption and subsequent reduction of OCPs in aquatic system.
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•Fe0-Biochar nanocomposites were synthesized using Nephelium lappaceum peel waste.•Morphology of Fe0-BRtP and Fe0-BChe nanocomposites was explored.•Six organochlorine pesticides removed involving adsorption and reduction mechanism.•Lower reactivity of aged Fe0-BChe nanocomposite, while Fe0-BRtP remained the same.•Regenerated Fe0-BRtP possesses good reusability even after five cycles.
Multifunctional food packaging films were developed based on chitosan (CS), nanosized TiO2 and black plum peel extract (BPPE). Effects of TiO2 and/or BPPE on the physical and functional properties of ...CS film were investigated. Results showed BPPE contained nine phenolic compounds with 23.29% of anthocyanins. The physical property of CS film could be significantly altered by incorporating TiO2 and/or BPPE. Notably, CSTiO2, CS-BPPE and CSTiO2-BPPE films all possessed higher barrier properties against water vapor and UV–vis light, and better mechanical strength than CS film. Scanning electron microscopy showed CS-BPPE film had a denser and smoother cross-section as compared to CS film. In addition, several white particles were clearly observed in the cross-section of CS-TO2 and CSTiO2-BPPE films. Fourier transform infrared spectroscopy and X-ray diffraction further revealed that CS could interact with TiO2 and BPPE through non-covalent bonds. Antioxidant assay showed CS-BPPE and CSTiO2-BPPE films both possessed strong free radical scavenging activity. Notably, CSTiO2-BPPE film exhibited the highest ethylene scavenging ability and antimicrobial activity among all films tested. Due to abundant anthocyanins in BPPE, the colors of CS-BPPE and CSTiO2-BPPE films were pH-sensitive. Our results suggest CSTiO2-BPPE film can be used as antioxidant, ethylene scavenging, antimicrobial and pH-sensitive food packing material.
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•Black plum peel extract (BPPE) contains abundant anthocyanins.•Multifunctional packaging films are developed using chitosan (CS), nano-TiO2 and BPPE.•TiO2 and BPPE can influence the property of CS film via intermolecular interactions.•CS-TiO2-BPPE film has antioxidant, ethylene scavenging and antimicrobial abilities.•CS-BPPE and CSTiO2-BPPE films possess pH-sensitive properties. .
MAIN CONCLUSION : Our studies showed that an apple B-box protein, MdCOL11, the homolog of AtBBX22, is involved in UV-B- and temperature-induced anthocyanin biosynthesis in apple peel. Anthocyanin is ...responsible for the red pigmentation in apple peel and a R2R3 MYB gene, MdMYBA/1/10, a homolog of MdMYBA, controls its accumulation. Arabidopsis PAP1 is under the control of a series of upstream factors involved in light signal transduction and photomorphogenesis, such as ELONGATED HYPOCOTYL 5 (HY5) and B-box family (BBX) proteins. In this study, we identified and characterized the homolog of Arabidopsis BBX22 in apple, designated as MdCOL11. Overexpression of MdCOL11 in Arabidopsis enhanced the accumulation of anthocyanin. In apples, MdCOL11 was differentially expressed in all tissues, with the highest expression in petals and the lowest expression in the xylem. Transcripts of MdCOL11 noticeably accumulated at the ripening stage, concomitant with increases in the expressions of anthocyanin biosynthesis-related genes. In an in vitro treatment experiment, MdCOL11 was upregulated in an ultra-violet (UV)-B- and temperature-dependent manner, together with the inductions of anthocyanin biosynthesis-related genes and anthocyanin accumulation in apple peel. Furthermore, a dual-luciferase assay indicated that (1) MdCOL11 regulated the expression of MdMYBA and (2) MdCOL11 was a target of MdHY5. Taken together, our results suggest that MdCOL11 is involved in MdHY5-mediated signal transduction and regulates anthocyanin accumulation in apple peel, which sheds new light on anthocyanin accumulation in apples.
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•A bioplastic was synthesized from citrus peel biomass.•Bioplastic is safely degradable and recyclable, enabling a perfect closed-loop cycle.•Bioplastics exhibit unique antioxidant ...and antimicrobial properties.•Bioplastics can extend the shelf life of perishable fruits.•The universality of this strategy was validated in a wide range of fruit peels.
The development of biodegradable antimicrobial bioplastics for food packaging holds great promise for solving the pollution and safety problems caused by petrochemical plastics and spoiled food. Herein, a natural active-bioplastic synthesized from citrus peel biomass is presented for perishable fruit preservation. These plastics are characterized by the nanoscale entanglement and recombinant hydrogen bonding between the endogenous pectin, polyphenols and cellulose micro/nanofibrils. They have attractive flexibility, tensile strength, gas barrier properties and antimicrobial activities, and can effectively extend the shelf life of perishable fruits such as banana and mango when used as food packaging. Cytotoxicity, degradability tests and life-cycle assessment show that these plastics had excellent nontoxicity and can be safely degraded or easily recycled. This work demonstrates a sustainable strategy for converting peel waste into eco-friendly bioplastics, providing a unique and novel insight into radically reducing the pollution and life-health threats posed by petrochemical plastics and spoiled food.
Cationic and anionic dyes are frequently used in industrial sectors and cause many environmental and health problems. Orange peel has the potential to absorb dye as an adsorbent. This study aimed to ...explore the adsorption of methylene blue (MB) as a cationic dye and methyl orange (MO) as an anionic dye using orange peel (OP) and its modification using cetyltrimethylammonium bromide (CTAB). OP and OP-CTAB biomass materials were characterized using FT-IR (Fourier transform infrared), surface area analysis using BET (Brunauer-Emmett-Teller) and SEM EDX (Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy). Based on the study results, OP has a microporous skin structure and OP-CTAB mesopores. Based on the effect of contact time, it is known that the best adsorption process on MB was to use OP adsorbent with the optimum amount of dye adsorbed produced at 50th minute that was 5.881 ppm, while the best adsorption process on MO was using OP-CTAB adsorbent with the optimum amount of dye was at 50th that was equal to 13.34 ppm. Based on the adsorption kinetics data, the adsorption of MO and MB dyes by OP and OP-CTAB followed the pseudo second order reaction kinetics model. The adsorption of MO and MB by both OP and OP-CTAB followed Langmuir's adsorption isotherm, meaning that the adsorption process in both MO and MB using OP and OP-CTAB appeared on homogeneous surface sites, while there was no interaction between adsorbate molecules and adjacent locations that means the adsorption process only occurred physically.
In order to improve adhesion properties of waterborne polyurethane (WPU) inks on biaxially oriented polypropylene (BOPP) films, herein, a liquid polyester polyol BY3003 with long‐branched aliphatic ...chains was used to prepare WPU latexes suitable for BOPP films printing. The application of BY3003 made the surface tension of the prepared latexes not more than 43 mN/m, while that of traditional WPU latex exceeded 55 mN/m. Accordingly, the T‐peel strength of the inks made from these latexes was all above 0.8 N/15 mm. In addition, post chain extension degree, dimethylol butyric acid content, and NCO/OH molar ratio also had significantly effect on latex and film properties of WPU, especially on the T‐peel strength of the corresponding inks. By optimizing these factors, a WPU latex with surface tension as low as 39.6 mN/m and adhesion fastness over 95% on BOPP film were obtained, and the T‐peel strength of its corresponding ink was up to 2.05 N/15 mm, which is the highest value recorded in the literature as far as we know.
Waterborne polyurethane latex was synthesised by using a long alkyl side chain containing polyester polyol, and the water‐based ink was prepared by using the as prepared latex as a binder. It is worth noting that the ink has good T‐peel strength, which is up to 0.25 N/15 mm.
In this study, dried orange peel powder DOPP is chemically modified with nanosilica (SiO2) employing sonication technique to produce nanobioadsorbent SiO2@DOPP. SiO2@DOPP This nanoadsorbent was ...evaluated for Cd2+ removal from aqueous systems. Successful functionalization of DOPP into nanosilica was confirmed by various analytical techniques like XRD, FTIR, SEM, EDX, TEM, DLS, pHzpc and TGA. XRD, FTIR and EDX confirmed the emergence of new peaks after modification of DOPP by nanosilica and adsorption of Cd2+ onto SiO2@DOPP. Further, TGA spectrum suggested that SiO2@DOPP nanoadsorbent is thermally more stable than DOPP. pH plays a major role to Cd2+ adsorption onto SiO2@DOPP. The optimum conditions for Cd2+ removal include pH = 6.5 and 0.03g adsorbent dose with 100 min contact time. Different adsorption isotherms models best fitted-(Langmuir adsorption model), adsorption kinetics best fitted–(Pseudo second order and Intraparticle diffusion) were examined for the removal of Cd2+. The maximum monolayer adsorption capacity qmax was 142 mg/g. Thermodynamic evaluation indicates the endothermic and spontaneous nature of Cd2+ adsorption onto SiO2@DOPP. Furthermore complexation mechanism of Cd2+ onto SiO2@DOPP is discussed in detail. The results indicate involvement of functional group interactions, π–metal interactions, proton exchange, chelate complexes and electrostatic interactions during adsorption of Cd2+ onto SiO2@DOPP. Based on the results it has been inferred that SiO2@DOPP is a promising nanobioadsorbent to manage environment burden of Cd2+ from aqueous systems.
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•Dried orange peel powder (DOPP) is chemically modified with nanosilica.•Functionalized nanobioadsorbent SiO2@DOPP has immense active binding sites for Cd2+ complexation.•SiO2@DOPP is thermally more stable than raw DOPP.•Six membered chelate co-ordination complex of Cd2+ is formed and its possible mechanism has been described.•The maximum monolayer adsorption capacity (Qmax) is 142 mg/g.
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