ABSTRACT
Nano-fibrillated cellulose (NFC) was extracted by a chemical method involving alkali and acid hydrolysis. The characterisation of the citrus sinensis fruit peel bran and nano-fibrillated cellulose was performed by XRD, FTIR, TEM, and FESEM. XRD confirmed the phase of NFC which showed monoclinic crystal with spherical to rod shape morphology with a size of 44-50 nm. The crystallinity index of treated NFC increased from 39% to 75%. FTIR showed the removal of lignin and hemicellulose from waste peels due to the alkaline treatment. Silver nanoparticles were also synthesised by utilizing extract of citrus sinensis skins as a reducing agent. Pharmaceutical effluent samples from an industrial area were tested by Atomic Absorption Spectrometry. Out of the four metals obtained, cadmium and chromium were remediated by silver nanoparticles with nano-fibrillated cellulose via simulated method in 100 mg/L metal-salt concentrations over a time period of 160 min. The highest removal efficiency was found for cadmium, i.e., 83%, by using silver and NFC together as adsorbents. The second highest was for chromium, i.e., 47%, but by using only NFC. The Langmuir and Freundlich isotherms were well fitted for the sorption of Cd (II) and Cr (II) with suitable high R2 values during kinetic simulation. Thus, the isolation of NFC and synthesis of silver nanoparticles proved efficient for heavy metal sorption by the reuse of waste skins.
ABSTRACT
Waste fruit peels which are usually discarded as agricultural wastes were utilized to isolate cellulose. The varied amount of isolated cellulose was used as sustainable support with hydrothermally synthesized molybdenum sulphide (MoS2) nano-petals via in-situ approach. The phase purity of all synthesized nanostructures was confirmed by PXRD whereas different oxidation states along with the interaction of cellulose with the MoS2 were examined by XPS analysis. In order to evaluate the performance of catalyst, the photodegradation rate was calculated for RhB dye as well as industrial effluent in visible light. The upgradation in photocatalytic competence was found significant by cellulose supported MoS2 nanostructures as compared to bare MoS2 nano-petals due to slow recombination of electron hole pairs. The maximum rate was pronounced by employing the cellulose at an amount of ~500 mg as a support due to existence of an optimal point where the delay in charge recombination reaches maximum.
Subject(s)
Molybdenum , Nanostructures , Cellulose , Disulfides , FruitABSTRACT
The efficiency and reusability of photocatalysts are the dominant factors for their pragmatic use. The visible light induced semiconductor silver phosphate is a superior photocatalyst effective under visible light but its stability is still an undiscussed issue. To overcome this stability issue in this present manuscript, eco-friendly agro-waste extracted cellulose supported silver phosphate nanostructures have been designed for the first time through a simple chemical process. At first, silver phosphate nanostructures were synthesized by the co-precipitation method. Then, different weights of cellulose were added to the silver nitrate solution to form cellulose supported silver phosphate nanostructures. The photodegradation efficiency for each weight ratio was examined in which the photocatalyst Ag-8 nanostructures showed a high rate (0.024 min-1) for degradation of Rhodamine B (RhB) using a low intensity tungsten bulb. Real sample analysis has also been carried out using this photocatalyst for the degradation of industrial fertilizer effluents. The degradation rate of all the nanostructures was found to be high in comparison to pristine silver phosphate as well as the extracted bare cellulose. The photocatalytic activity is enhanced because of the participation of cellulose as a support which makes an interface for silver phosphate and assists it in delaying the charge recombination period under visible light. To understand the photochemical reaction of electrons and holes, scavenger studies were also performed.
ABSTRACT
Agro-waste-extracted cellulose-supported CuInS2 nanocomposites were hydrothermally synthesized with significant photocatalytic activity under the influence of cellulose as a polymeric natural support that offers delay in electron-hole life. Delayed recombination process of electrons and holes was perceived by parting of cellulose as a barrier or edge during photochemical reaction, which overall enhances the lifetime of photocatalyst. The photodegradation efficiency over five consecutive cycles along with scavenging studies have been examined for RhB dye under visible light. The boosted photodegradation rate was observed at an optimum amount of cellulose (200 mg), which is â¼10 times higher than pristine CuInS2.
