scholarly journals Green Tea Leaves as a Natural Adsorbent for the Removal of Cr(VI) from Aqueous Solutions

2016 ◽  
Vol 9 ◽  
pp. ASWR.S35227 ◽  
Author(s):  
Christine Jeyaseelan ◽  
Astha Gupta

Chromium(VI) has been found to be one of the toxic metals present in water obtained from industrial effluents. This study deals with the removal of Cr(VI) using used green tea leaves, which is a waste material. The sorption of Cr(VI) was carried out by using a batch method, and its concentration was determined using an ultraviolet visible spectrophotometer at 540 nm. Parameters such as pH, mass of adsorbate, concentration of adsorbent, time of contact, and temperature were optimized. It was observed that, under optimum conditions, the percentage efficiency of removal of Cr(VI) was up to 99%. Adsorption studies were carried out using Langmuir and Freundlich adsorption isotherms. The values of Δ G, Δ H, and Δ S were also calculated, which showed that the process is spontaneous and the extent of adsorption decreases with the increase in temperature. The kinetic studies were carried out, and it was found that the reactions followed pseudo-second-order kinetics. This technique can be used for the removal of Cr(VI) from water obtained from industries, which have chromium as one of the main pollutants in their effluents.

2007 ◽  
Vol 12 (1) ◽  
pp. 35-39 ◽  
Author(s):  
Dae-Jin Kim ◽  
Dae-Soo Chung ◽  
Sung-Chul C. Bai ◽  
Hyeong-Soo Kim ◽  
Yu-Bang Lee

Author(s):  
Ali Forouzanfar ◽  
Hamideh Sadat Mohammadipour ◽  
Fatemeh Forouzanfar

: Periodontal diseases are highly prevalent and can affect high percentage of the world population. Oxidative stress and inflammation plays an important role in the pathogenesis of periodontal diseases. Nowadays, more attention has been focused on the herbal remedies in the field of drug discovery. Green tea is an important source of polyphenol antioxidants, it has long been used as a beverage worldwide. The most interesting polyphenol components of green tea leaves that are related with health benefits are the catechins. Taken together this review suggested that green tea with its wide spectrum of activities could be a healthy alternative for controlling the damaging reactions seen in periodontal diseases.


2021 ◽  
Vol 1795 (1) ◽  
pp. 012070
Author(s):  
Hamsa A. Abdulmageed ◽  
Abdulhadi. K. Judran ◽  
Farah T. M. Noori

Cellulose ◽  
2021 ◽  
Author(s):  
Nina Čuk ◽  
Martin Šala ◽  
Marija Gorjanc

Abstract The development of cellulose-based textiles that are functionalised with silver nanoparticles (AgNP), synthesised according to a green approach, and offer protection against ultraviolet (UV) radiation and pathogenic bacteria is very important today. In the present work we demonstrate the environmentally friendly approach to obtain such textile material by AgNP synthesis directly (in-situ) on cotton fabrics, using water extracts of plant food waste (green tea leaves, avocado seed and pomegranate peel) and alien invasive plants (Japanese knotweed rhizome, goldenrod flowers and staghorn sumac fruit) as reducing agents. The extracts were analysed for their total content of phenols and flavonoids and their antioxidant activity. The synthesised AgNP on cotton were round, of different size and amount depending on the reducing agent used. The highest amount of AgNP was found for samples where Japanese knotweed rhizome extract was used as reducing agent and the lowest where extracts of goldenrod flowers and green tea leaves were used. Regardless of the reducing agent used to form AgNP, all cotton samples showed excellent protection against E. coli and S. aureus bacteria and against UV radiation with UV protection factor values above 50. The best results for UV protection even after the twelve repetitive washing cycles were found for the sample functionalized with AgNP synthesised with an extract of the Japanese knotweed rhizome. Due to the presence of AgNP on cotton, the air permeability and thermal conductivity decreased. AgNP had no effect on the change in breaking strength or elongation of fabrics. Graphic abstract


2021 ◽  
Author(s):  
Zhu-Lin Luo ◽  
Hongyu Sun ◽  
Xiao-Bo Wu ◽  
Long Cheng ◽  
Jian-Dong Ren

Green tea has been considered as a health-promoting beverage and is widely consumed worldwide. Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol derived from green tea leaves with potent antioxidative and chemopreventive...


2009 ◽  
Vol 58 (8) ◽  
pp. 699-706 ◽  
Author(s):  
Hua Jin ◽  
Akhmad Sabarudin ◽  
Mitsuko Oshima ◽  
Shoji Motomizu

2018 ◽  
Vol 23 (3) ◽  
pp. 124
Author(s):  
Fransiska Lisa Anindya Putri ◽  
Akhmad Kharis Nugroho ◽  
Erna Prawita Setyowati

Green tea (Camellia sinensis L.) is known to have ability to protect skin against free radicals. This is supported by polyphenol compound catechin. This research aims to determine the optimum Hydrophilic-Lipophilic Balance (HLB) value of Tween 60 and Span 80 compositions on the optimum cream formula of ethanol extract of green tea leaves. Tea leaves are extracted by macerating using 70% ethanol. Catechin in extract is known from Thin Layer Chromatography (TLC) test with silica gel 60 F254 as stationary phase and ethyl acetate:aquadest:formic acid (18:1:1 v/v) as mobile phase. Antioxidant activity is determined by 2,2-Diphenyl-1-picryhydrazyl (DPPH) method and value of Inhibition Concentration 50% (IC50) is then calculated. Formula optimization using Design Expert® version 7.1.5 (DX 7) software, Simplex Lattice Design (SLD) method with two components Tween 60 and Span 80. Cream is characterized according to physical properties organoleptic, homogeneity, viscosity, pH, spreadability, adhesiveness, and cream type. The optimum formula obtained is then tested for physical stability for 4 weeks at room temperature (28±2°C) and data are statistically analyzed using one-way ANOVA. The extract contains catechin proved with Retention factor (Rf) value 0.8 and has antioxidant activity with IC50 value 56.35 ppm. 6.4% Tween 60 and 3.6% Span 80 result an optimum HLB value 11.1. It has viscosity 2897.50±35.94 mPa.s, spreadability 18.44±0.06 cm2, adhesiveness 0.85±0.05 seconds, and pH 4.530±0.002. Statistical test shows that the cream is significantly altered at pH, but does not significantly change in viscosity, spreadability, and adhesiveness after being stored for 4 weeks.


2012 ◽  
Vol 27 ◽  
pp. 11-18
Author(s):  
Timi Tarawou ◽  
Michael Horsfall

The adsorption of chromium (VI) ions from aqueous solution was studied using pure and carbonized fluted pumpkin waste biomass (FPWB). The kinetic data shows a pseudo-first-order mechanism with rate constants of 1.26 × 10-2 and 1.933 × 10-2 mg g-1 min-1 for the pure and carbonized FPWB, respectively. While the pseudo-second-order mechanism has rate constants of 0.93 × 10-1 and 1.33 × 10-1 mg g-1 min-1 for the pure and carbonized waste biomass respectively. The pseudo-second order kinetic model was found to be more suitable for describing the experimental data based on the correlation coefficient values (R2) of 0.9975 and 0.9994 obtained for pure waste biomass (PWB) and carbonized waste biomass (CWB), respectively. The results obtained from this study show that PWB and CWB have very high removal capacity for chromium (VI) from aqueous solution over a range of reaction conditions. Thus, fluted pumpkin waste biomass (Telfairia occidentalis Hook F) is a potential sorbent for the treatment of industrial effluents containing chromium (VI) contaminant.DOI: http://dx.doi.org/10.3126/jncs.v27i1.6436 J. Nepal Chem. Soc., Vol. 27, 2011 11-18Uploaded date: 16 July, 2012


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