Modified Bamboo Charcoal as a Bifunctional Material for Methylene Blue Removal

Abstract

Biomass-derived raw bamboo charcoal (BC), NaOH-impregnated bamboo charcoal (BC-I), and magnetic bamboo charcoal (BC-IM) were fabricated and used as bio-adsorbents and Fenton-like catalysts for methylene blue removal. Compared to the raw biochar, a simple NaOH impregnation process significantly optimized the crystal structure, pore size distribution, and surface functional groups and increase the specific surface area from 1.4 to 63.0 m2/g. Further magnetization of the BC-I sample not only enhanced the surface area to 84.7 m2/g, but also improved the recycling convenience due to the superparamagnetism. The maximum adsorption capacity of BC, BC-I, and BC-IM for methylene blue at 328 K was 135.13, 220.26 and 497.51 mg/g, respectively. The pseudo-first-order rate constants k at 308 K for BC, BC-I, and BC-IM catalytic degradation in the presence of H2O2 were 0.198, 0.351, and 1.542 h−1, respectively. A synergistic mechanism between adsorption and radical processes was proposed.

Black Tea Waste as Green Adsorbent for Nitrate Removal from Aqueous Solutions

“…By increasing the initial concentrations of nitrite, the specific sites of the adsorbents become saturated, and the exchange sites fill up. Although the kinetics of the process are slowed by higher initial nitrate concentrations, the uptake percentage increases [ 6 , 19 ].…”

“…Recent findings from laboratory research indicate that it may be possible to develop effective and reasonably priced adsorbents using various by-products from the agro-food industry, such as tea waste, coffee waste, or seed and fruit waste, to remove organic compounds and heavy metals from contaminated aquatic environments. An abundant natural substance or one that is a waste product or byproduct of industry or agriculture that requires little to no processing is considered a low-cost adsorbent [ 5 , 6 , 7 , 8 , 9 , 10 ].…”

“…The adsorption method is a simple, easy-to-use, and scalable method of contaminant removal [ 19 , 24 ]. For the removal of nitrate ions from aqueous solutions, a variety of adsorbents have been used, including hybrid nanocomposites, activated carbon, anionic layer double hydroxide, and magnetic nanoparticles [ 6 , 25 ].…”