Facile Preparation of Porous Carbon Derived from Pomelo Peel for Efficient Adsorption of Methylene Blue

Pomelo peel waste-derived porous carbon (PPPC) was prepared by a facile one-step ZnCl₂ activation method. The preparation parameters of PPPC were the mass ratio of ZnCl₂ to pomelo peel of 2:1, carbonization temperature of 500 °C, and carbonization time of 1 h. This obtained PPPC possessed abundant macro-,meso-, and micro-porous structures, and a large specific surface area of 939.4 m² g^-1. Surprisingly, it had excellent adsorption ability for methylene blue, including a high adsorption capacity of 602.4 mg g^-1 and good reusability. The adsorption isotherm and kinetic fitted with Langmuir and pseudo-second order kinetic models. This work provides a novel strategy for pomelo peel waste utilization and a potential adsorbent for treating dye wastewater.

Multi-step preparation of Fe and Si modified biochar derived from waterworks sludge towards methylene blue adsorption

A magnetic nitrogen-doped sludge-based biochar (NAlSB-Fe-Si) was prepared based on waterworks sludge for raw material and dicyandiamide for nitrogen source to adsorb methylene blue (MB) from water. And the magnetic particles loaded on the adsorbent were obtained through functionalizing iron and silicon ions which were extracted from the biochar by acid and alkali impregnation. Physicochemical properties of sludge-based biochar (SB) were analyzed by SEM, BET, FTIR, XRD, XPS and VSM. Compared with the original biochar, NAlSB-Fe-Si had richer pore structure and higher pore volume, and the SiO₂ and Fe₃O₄ loading made the specific surface area increased by 200%. Possible adsorption mechanism was proposed by exploring the initial pH, MB concentration and reaction time. Results revealed that alkaline environment was more conducive to the rapid removal of cationic dyes such as MB. Pseudo-second-order kinetic model and intra-particle diffusion model could describe the adsorption behavior of MB on NAlSB-Fe-Si. The fitting results of Langmuir model showed that adsorption temperature is positively correlated with adsorption capacity, and the maximum adsorption capacity of MB on nitrogen-doped sludge-based biochar (NSB) and NAlSB-Fe-Si at 25 °C was 26.47 and 300.36 mg/g, respectively. Finally, the MB removal rate of NAlSB-Fe-Si could still reach 70% after four cycles, indicating that the composite was an efficient cationic dye adsorbent, and its preparation could be regarded as a way of resource utilization of waterworks sludge.

Nano Porous Carbon Derived from Citrus Pomace for the Separation and Purification of PMFs in Citrus Processing Wastes

The by-product of citrus juice processing is a huge source of bioactive compounds, especially polymethoxyflavones (PMFs) and fibers. In this study, a method for the separation and purification of PMFs from citrus pomace was established based on citrus nanoporous carbon (CNPC) enrichment. Different biomass porous carbons were synthesized, their adsorption/desorption characteristics were evaluated, and the CNPCs from the peel of Citrus tangerina Tanaka were found to be best for the enrichment of PMFs from the crude extracts of citrus pomace. Using this method, six PMF compounds including low-abundant PMFs in citrus fruits such as 5,6,7,4'-tetramethoxyflavone and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone can be simultaneously obtained, and the purities of these compounds were all higher than 95%, with the highest purity of nobiletin reaching 99.96%. Therefore, CNPCs have a great potential for the separation and purification of PMFs in citrus processing wastes, potentially improving the added value of citrus wastes. We also provide a method reference for disposing of citrus pomace in the future.

Synchronous role of coupled adsorption and photocatalytic oxidation on the hybrid nanomaterials of pectin and nickel ferrite leads to the excellent removal of toxic dye effluents

Ecofriendly and robust hybrid nanomaterials of pectin and nickel ferrite were succesfully employed for the adsorptive degradation of toxic dye molecules in waste water treatment.

Citrus Pectin-Derived Carbon Microspheres with Superior Adsorption Ability for Methylene Blue

In this study, citrus pectin-derived, green, and tunable carbon microspheres with superior adsorption capacity and high adsorption rate, as well as good reusability toward methylene blue adsorption, were prepared by a facile hydrothermal method without any hazardous chemicals. The materials hold great potential for the treatment of methylene blue wastewater.

Rational design of hierarchical macroporous–mesoporous magnesium silicate for highly efficient removal of organic dye and Pb2+

Magnesium silicate with a hierarchical macroporous–mesoporous nanostructure favours the mass transportation of pollutants and exhibits excellent removal performance for methylene blue and Pb²⁺.