Study on Adsorption Characteristics of Heavy Metal Cd²⁺ by Biochar Obtained from <i>Water Hyacinth</i>

Abstract

In this paper, the biochar prepared by pyrolysis biomass of Water Hyacinth were used as adsorption materials. The effects of initial concentration, adsorption temperature and electrolyte concentration on the adsorption process were analyzed. The adsorption effect of biochar prepared from the stem and root parts of biomass on Cd 2+ in solution was investigated, and the interaction between leaching rule of alkali (earth) metal K + , Mg 2+ , Ca 2+ and adsorption of heavy metal ions in the process of adsorption was studied. The results showed that the biochar prepared by pyrolysis of stem biomass (SBC) has a richer pore structure. Compared with the biochar prepared by root biomass (RBC), the specific surface area and pore volume of SBC increased by 25.85% and 27.91% respectively. This phenomenon indicated that SBC had a stronger adsorption effect than RBC. At 25ºC, the maximum adsorption capacity of RBC and SBC for Cd 2+ was 77.20 mg g -1 and 87.20 mg g -1 , respectively. Isothermal adsorption experiments and ionic strength experiments showed that the increase of temperature could promote the adsorption of Cd 2+ by biochar. The adsorption process has a high degree of fitting with the Langmiur model, as well as the pseudo-second-order model. The adsorption sites were normally on the inner and outer surfaces of biochar, and the adsorption process was multi-molecular layer adsorption. In addition, the adsorption of Cd 2+ by biochar had a correlation with the leaching of alkali (earth) metal in the system. In the adsorption process, the leaching of alkali (earth) metals was affected by the initial concentration of Cd 2+ in the solution, and SBC leached more alkali (earth) metals than RBC, which proved that SBC has more

Application of Water Hyacinth Biomass (Eichhornia crassipes) as an Adsorbent for Methylene Blue Dye from Aqueous Medium: Kinetic and Isothermal Study

“…It is evident that the water hyacinth as a raw material for the constitution of bioadsorbents has natural advantages, such as a spongy structure with large cellular gaps, which can generate a significant specific surface area. In general, the greater the specific surface area of the biomass, the greater the pore volume, which can provide greater adsorption capacity [64]. Its surface presents a slightly more basic character, indicating that it can adsorb cationic dyes more easily in a certain pH range, but it also includes some acidic characteristics, indicating the presence of different active sites on its surface.…”

Investigation of the Desalination Capacity of Activated Carbon Materials from Water Hyacinth (<i>Eichhornia crassipes</i>) Stems

“…Despite bringing many potential threats, water hyacinth is still favorably employed for its uses, such as agricultural wastewater treatment and adsorption of heavy metal ions [17][18][19][20][21][22][23][24][25]. Research to take advantage of this biomass in daily life is being expanded, in which the production of activated carbon from water hyacinth stems is also focused.…”