The surface of a biowaste was modified by introduction of amino group for the purification of wastewater contaminated with heavy metals. In this study waste tea leaf was used as a biowaste which was an economic and efficient bioadsorbent. The aminated tea leaves were characterized by spectral and elemental analysis. The adsorption capacity of the surface modified biosorbent was studied as the function of solution pH, concentration of metal ions and contact time of adsorption. The applicability of Langmuir isotherm was tested. The adsorption capacities were found to be 83.04 mg/g and 57 mg/g for Pb (II) and Cd (II), respectively. The biosorbent was regenerated by desorption of the metal loaded adsorbent with 0.1 M HNO 3. These results showed that the aminated tea leaves may be an attractive alternative for treatment of wastewater contaminated with heavy metals.

In the present work an efficient and cost-effective biosorbent was prepared by chemical modification of tealeaves. Amine-functional group was introduced on the surface of adsorbent using dimethylamine. The adsorbent was characterized by SEM, FTIR and elemental analysis. The adsorption capacity of the adsorbent for Cd (II) was determined as the function of pH of the solution, concentration of metal ions and contact time. The maximum adsorption was found to be 77 mg/g at pH 6. Nepal Journal of Science and Technology Vol. 13, No. 2 (2012) 109-114 DOI: http://dx.doi.org/10.3126/njst.v13i2.7722

In this study adsorptive removal of Pb(II) and Cu(II) from aqueous solution by using environmental friendly natural polymers present in exhausted tea leaves has been studied. The biosorbent was modified with dimethylamine to introduce N-functional groups on the surface of adsorbent. The modified adsorbent was characterized by elemental analysis, zeta potential analysis, SEM, DRFTIR, XRD and TG/DTA analysis to conform the modification. Adsorption capacity of the adsorbent was determined as the function of pH of the solution, initial concentration of the solution and contact time. The adsorption experiments were performed using batch experiments. The maximum adsorption capacities of the adsorbent were found to be 91.68 and 71.20 mg/g for Pb(II) and Cu(II), respectively. To minimize the process cost, regeneration of the biosorbent and recovery of metal ions was explored by desorption study. The results indicate that the adsorbent holds great potential for the sequestration of Pb(II) and Cu(II) from their aqueous solution. Hence the modified exhausted tea leaves (MTL) have been investigated as a new cost effective and efficient biosorbent for removal of Pb(II) and Cu(II) from their aqueous solution.

An efficient and cost effective bioadsorbent has been prepared from exhausted tea leaves using hydrazine monohydrate. The aminated tea leaves (ATL) was characterised by elemental and spectral analysis. The batch adsorption study was performed using ATL for the removal of Pb++ and Zn++ from their aqueous solution. Adsorption experiment was conducted as the function of solution pH, initial metal concentration and contact time. The maximum adsorption capacity of the adsorbent was found to be 120.8 mg/g for Pb++ and 79.76 mg/g for Zn++. These results indicated that the aminated tea leaves hold great potential to remove Pb++ and Zn++ from aqueous solution.DOI: http://dx.doi.org/10.3126/jncs.v30i0.9383Journal of Nepal Chemical Society Vol. 30, 2012 Page: 123-129 Uploaded date: 12/20/2013

Recycling technology contributes to sustainability and has received considerable interest in fulfilling consumable products' social demands, including papers. Recycled fibers are the primary source of the papermaking industry. Papers, valuable daily used materials, can be further recycled for further implementation. Here, we report a simple method for recycling waste papers for further use. Our method includes re-pulping, deinking, bleaching, and papermaking. The sample and the recycled papers were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). XRD data shows the presence of cellulose and filler minerals in the sample and the recycled papers. FTIR analysis confirmed the presence of hydroxyl, carbonyl, and methyl functional groups in the recycled papers suggesting that the deinking and bleaching did not cause any structural changes. The fibrous structures were also sustained after recycling, as confirmed by SEM studies demonstrating that the recycling was successful and the papers can be further used and recycled. EDS analysis further confirmed the filler minerals in the sample paper with a trace amount of lead, which decreased upon bleaching the paper. The structure and properties of the sample and the recycled papers were quite similar, inferring that waste papers can be recycled again and different products from low to higher grade papers can be fabricated.