Using Biochar and Nanobiochar of Water Hyacinth and Black Tea Waste in Metals Removal from Aqueous Solutions

Abstract

The treatment of heavy metal-contaminated water is challenging. The use of nanomaterials from many environmental wastes is promising for removing metals and contaminants from aqueous solutions. This study is novel in using nanobiochar of water hyacinth (WH) and black tea waste (TW) as a promising approach to water decontamination owing to its unique properties that play an effective role in metal adsorption. The mono- and multi-adsorption systems of cadmium (Cd), chromium (Cr), and nickel (Ni) on biochar and nanobiochar of water hyacinths (BWH and NBWH) and black tea waste (BTW and NBTW) were investigated in this study as potential low-cost and environmentally friendly absorbents for the removal of previously mentioned heavy metals (HMs) from aqueous solutions. The WH and TW were collected from the locality, prepared, and kept until used in the experiment. Nanobiochar was prepared by grinding, characterizing, and storing in airtight containers until used. A batch experiment was designed in mono- and competitive systems to study the adsorption equilibrium behavior of HMs on biochar and nanobiochars. The Freundlich and Langmuir isotherm models were fitted to the mono- and competitive-adsorption equilibrium results. The Freundlich isotherm model provided a better fit. Furthermore, it was noticed that NBWH and NBWT efficiently removed the Cd in the mono-system by ≥99.8, especially in the smaller concentration, while NBWT and BTW removed ≥99.8 and 99.7% in the competitive system, respectively. In the mono- and competitive systems, the nanobiochars of NBTW removed more than 98.8 of Cr. The sorbents were less efficient in Ni removal compared to Cd and Cr. However, their effectiveness was very high also. The results revealed that Cd was the highest metal removed by sorbents, nanobiochars were better than biochars to remove the HMs, and the results also indicated that co-occurrence of multi-metals might fully occupy the adsorption sites on biochars and nanobiochars.

A review of important heavy metals toxicity with special emphasis on nephrotoxicity and its management in cattle

“…Biochar lowers the bioavailability of harmful metals and raises the pH of the soil ( 282 ). Additionally, biochar has the potential to enhance soil quality and drastically lower the bioavailability of hazardous metals ( 283 ). Biomass is pyrolyzed to make biochar ( 282 ).…”

“…To avoid the undesirable outcome of surface water and groundwater contamination, landfill leachate should be gathered and properly treated. Leachate is produced as a result of waste degradation or water access, and it can contaminate groundwater and soil ( 282 , 283 ). A source of contamination in cattle is metal-containing leachate.…”

Comparison of adsorption performance for Cd(II) removal from aqueous solution using biochar derived from different types of carbon sources: aquatic plants, pine branches and peat

“…Relevant studies have shown that herb‐based biochar has an outstanding treatment performance on contaminants Cd(II) and Pb(II). For example, biochar prepared via the pyrolysis of aquatic plants has the characteristics of rougher surfaces and porous and rich oxygen‐containing functional groups (OCFGs), and is very suitable as an adsorption material for adsorbing heavy metals in wastewater 4,7,8 . However, since the biochar produced by pyrolysis is directly used as the adsorbent, its specific surface area (SSA) and surface OCFG content are still lower than those of the modified biochar.…”

“…For example, biochar prepared via the pyrolysis of aquatic plants has the characteristics of rougher surfaces and porous and rich oxygen-containing functional groups (OCFGs), and is very suitable as an adsorption material for adsorbing heavy metals in wastewater. 4,7,8 However, since the biochar produced by pyrolysis is directly used as the adsorbent, its specific surface area (SSA) and surface OCFG content are still lower than those of the modified biochar. The direct use of biochar as adsorbent to remove heavy metals in water cannot achieve satisfactory results.…”

Efficient Catalytic Degradation of Selected Toxic Dyes by Green Biosynthesized Silver Nanoparticles Using Aqueous Leaf Extract of Cestrum nocturnum L.

“…In the present scenario, different metals such as Ag, Au, Pd, Cu, and Zn are used in the synthesis of nanoparticles [ 3 ]. Biosynthesized green NPs are preferred due to their low toxicity, biocompatibility, cost-effectiveness, and sustainability for the environment [ 4 , 5 , 6 , 7 ]. In the biosynthesis of the green NPs, algae [ 8 ], fungi [ 9 ], bacteria [ 10 ], and plant extracts [ 11 ] are utilized.…”