Elemental mercury removal by the modified bio-char from waste tea

Shen, Bo; Tian, Liyan; Li, Fukuan; Zhang, Xiao; Xu, Huan; Singh, Surjit

doi:10.1016/j.fuel.2016.09.059

Cited by 105 publications

(50 citation statements)

References 53 publications

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“…The growth of the tea industry further promoted the consumption of tea. The reported output of tea in China in 2015 was 2.27 million tons, which was greater than 40% of the global output that year (Shen et al 2017). Every year, given the high demand for tea products, a large amount of waste tea is generated after extraction.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterisation of activated carbon from waste tea by physical activation using steam

Zhou

Luo

Zhao

2018

Journal of the Air & Waste Management Association

142

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In this study, the feasibility of preparing activated carbon from waste tea by physical activation using steam was investigated. The effects of activation temperature on yield and pore properties of the prepared activated carbon were studied. The yield decreased with increased activation temperature owing to the decomposition of cellulose and hemicellulose. The specific surface area and pore volume of the activated carbon were estimated using the Brunauer-Emmett-Teller method, Langmuir equation, and t-plot method. The specific surface area and micropore volume increased with increases in activation temperature, as additional volatile materials were released. The specific surface area significantly decreased at first but slightly increased with increasing activation time. The maximum specific surface area reached 995 m/g at an activation temperature of 800 °C with a water flow rate of 0.075 g/min and a constant hold time of 0.5 hr. According to the nitrogen adsorption isotherms, micropores mainly developed when the activation temperature was below 800 °C, and both micropores and mesopores developed when it was above 800 °C. The results showed that activation temperature significantly affected micropore and mesopore volumes, as well as the specific surface area of the activated carbon. Overall, waste tea was found to be an attractive raw material for producing low-cost activated carbon. Implications: Every year, a large amount of waste tea is generated after extraction. The high carbon content of waste tea showed that it can be used as raw material to produce activated carbon. This study investigated the feasibility of preparing activated carbon from waste tea by physical activation using steam. Temperature and time were found to have clear effects on pore properties. Our proposed method and raw material are more environmentally friendly and involve low cost. Furthermore, this offers a potential solution to the problems of waste tea disposal and low-cost activated carbon production.

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Section: Introductionmentioning

confidence: 99%

Preparation and characterisation of activated carbon from waste tea by physical activation using steam

Zhou

Luo

Zhao

2018

Journal of the Air & Waste Management Association

142

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“…Kaolin was not only the best natural Hg adsorbent among clays (Figure ) but also efficient in comparison to the other reported Hg 0 adsorbents, which include activated carbon, charcoal and char …”

Section: Resultsmentioning

confidence: 99%

“…Kaolin was not only the best naturalH ga dsorbent among clays ( Figure 1) but also efficient in comparison to the other reported Hg 0 adsorbents,w hich include activated carbon,c harcoal and char. [14] The production and use of kaolin are commona round the world. For instance, in 2017, the United States (US) produced, imported, exported, and used 5500, 480, 2300 and 160 metric tons of kaolin, respectively.I nt erms of the production amount, kaolin is second only to commonc lay( Figure S2).…”

Section: Resultsmentioning

confidence: 99%

Natural Kaolin: Sustainable Technology for the Instantaneous and Energy‐Neutral Recycling of Anthropogenic Mercury Emissions

et al. 2019

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Kaolin, a natural and inexpensive clay mineral, is ubiquitous in soil, dirt, and airborne particles. Amongst four commonly available clay minerals, kaolin, as a result of its layered structure, is the most efficient natural gaseous Hg adsorbent to date (Langmuir maximum adsorption capacity Qm=574.08 μg g−1 and Freundlich Qm=756.49 μg g−1). The Hg uptake proceeds by homogeneous monolayer and heterogeneous processes. Hg physisorption on kaolin occurs in the dark, yet the adsorption rate is enhanced upon irradiation. The effects of several metal complexes, salts, halides and solvents on the Hg uptake were examined. The addition of CuCl2 particles leads to a significant enhancement of the Hg uptake capacity (>30 times) within second timescales and without irradiation. The physisorption with kaolin is switched to chemisorption upon the addition of CuCl2 to kaolin. This process is entirely reversible upon the addition of Zn/Sn granules at room temperature without any added energy. However, the investment of a small amount of renewable energy can speed up the process. This technology demonstrates the facile and efficient capture and recycling of elemental Hg0 from air. A wide range of metal particles and diverse physicochemical processes, which include the microphysics of nucleation, are herein examined to explore the potential reaction mechanism by using a suite of complementary analytical techniques. These new mechanistic insights open a new era of energy‐neutral environmental remediation based on natural soil/airborne particles.

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“…The thermodynamic studies also indicated that the process was spontaneous, feasible, and endothermic. Several other recent and relevant studies reported on mercury adsorption using different adsorbents are discussed …”

Section: Purification Of Mercury‐containing Wastewater Using Low‐costmentioning

confidence: 99%

Trapping Ionic Mercury Using Different Adsorbents

Ojedokun

Oluwole

Bello

2019

CLEAN Soil Air Water

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Of recent, adsorption process has gained a lot of attention as a cheap and effective means of removing trace metals from wastewater prior to discharge into water bodies. Being flexible in design and operation, the process has enabled an optimal recovery of trace metals such that the treated effluents meet the desired standards for waste disposal. Mercury is a toxicant released into the environment from natural and anthropogenic sources. It is notorious for having an unusual tendency to bio‐accumulate and persist in the food chain. Presence of mercury in food, especially those of aquatic sources has drastic implications on human health. Therefore, efforts have been made to develop and optimize low‐cost activated carbon (AC) as adsorbents for scavenging mercury from aqueous effluents. Herein, how mercury accumulates across the food chain, its health implications, and the recent advancement in the use of low‐cost ACs as adsorbent for trapping mercury from wastewater are highlighted. Relationship between the mercury removal efficiency and the surface morphology of the adsorbents as well as the influence of prevailing experimental condition on the sorption process were addressed. Challenges and future prospects of the use of low‐cost adsorbents in addressing mercury pollution in the environment are discussed.

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Elemental mercury removal by the modified bio-char from waste tea

Cited by 105 publications

References 53 publications

Preparation and characterisation of activated carbon from waste tea by physical activation using steam

Preparation and characterisation of activated carbon from waste tea by physical activation using steam

Natural Kaolin: Sustainable Technology for the Instantaneous and Energy‐Neutral Recycling of Anthropogenic Mercury Emissions

Trapping Ionic Mercury Using Different Adsorbents

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