Statistical analysis of Cu(II) and Co(II) sorption by apple pulp carbon using factorial design approach

New alginate-based interpenetrating polymer networks for water treatment: A response surface methodology based optimization study

Different interpenetrating polymeric networks (IPN) based on sodium alginate, carrageenan and bentonite were developed to remove heavy metals and dyes from contaminated water. Four significant preparation factors; crosslinking time, calcium chloride concentration, alginate to carrageenan mass ratio,and bentonite to carrageenan mass ratio were studied and optimized via full factorial design and response surface methodology to determine the optimum composition with highest adsorption capacity. Different optimal conditions and combinations were found depending on the type of heavy metal or dye to be removed. Low calcium chloride concentration was a common factor in all cases of heavy metals and dyes removal which indicates the negative effect of excessive crosslinking on the removal percentage. The adsorption capacity of methylene blue, Fe³⁺, Ni²⁺, and Cr³⁺ ions is 1271, 1550, 1500 and 1540 mg/g adsorbent, respectively. Reusability tests confirmed that the optimized formulations can be reused five successive times without significant drop in their removal efficiency. Upon utilization of the optimized formulations on real contaminated waters from tannery plant and oasis groundwater, they demonstrated an excellent performance as they removed above 95% of the original heavy metals contaminants and 40% of the acidic dye content.

Removal of copper ions from aqueous solution using low temperature biochar derived from the pyrolysis of municipal solid waste

Sustainable methods to produce filter materials are needed to remove a variety of pollutants found in water including organic compounds, heavy metals, and other harmful inorganic and biological contaminants. This study focuses on the removal of Cu(II) from copper aqueous solutions using non-activated char derived from the pyrolysis of mixed municipal discarded materials (MMDM) using a new heat pipe-based pyrolysis reactor. Adsorption experiments were conducted by adding the char to copper solutions of varying concentration (50-250 mg/L) at a constant temperature of 30 °C. The effect of pH on copper adsorption onto the char was also investigated in the range of pH 3 to 6. Copper removal using the char was found to be heavily dependent on pH, adsorption was observed to decrease below a pH of 4.5. However, the initial copper concentration had a little effect on the sorption of copper at high concentration solutions (above 100 mg/L). Overall, the biochar showed an effective copper adsorption capacity (4-5 mg/g) when using copper solutions with a concentration below100 mg/L and pH >4.5. Copper removal using the char tended to follow the pseudo second order kinetic model. Langmuir isothermal model was shown to be the closest fitting isotherm using the linearized Langmuir equation. However, the variety of feedstock used to produce the char led to a variation in results compared to other studies of more specific feedstocks.