Na₄P₂O₇-Modified Biochar Derived from Sewage Sludge: Effective Cu(II)-Adsorption Removal from Aqueous Solution

Abstract

With the rapid development of industrialization, the amount of copper-containing wastewater is increasing, thereby posing a threat to the aquatic ecological environment and human health. Sludge biochar has received extensive concern in recent years due to its advantages of low cost and sustainability for the treatment of heavy-metal-containing wastewater. However, the heavy-metal-adsorption capacity of sludge biochar is limited. This study prepared a sodium pyrophosphate- (Na4P2O7-) modified municipal sludge-based biochar (SP-SBC) and evaluated its adsorption performance for Cu(II). Results showed that SP-SBC had higher yield, ash content, pH, Na and P content, and surface roughness than original sewage sludge biochar (SBC). The Cu(II)-adsorption capacity of SP-SBC was 4.55 times than that of SBC at room temperature. For Cu(II) adsorption by SP-SBC, the kinetics and isotherms conformed to the pseudo-second-order model and the Langmuir–Freundlich model, respectively. The maximum adsorption capacity of SP-SBC was 38.49 mg·g−1 at 35°C. Cu(II) adsorption by SP-SBC primarily involved ion exchange, electrostatic attraction, and precipitation. The desired adsorption performance for Cu(II) in the fixed-bed column experiment indicated that SP-SBC can be reused and had good application potential to treat copper-containing wastewater. Overall, this study provided a desirable sorbent (SP-SBC) for Cu(II) removal, as well as a new simple chemical-modification method for SBC to enhance Cu(II)-adsorption capacity.

Properties and Possibilities of Using Biochar Composites Made on the Basis of Biomass and Waste Residues Ferryferrohydrosol Sorbent

“…The creation of composites was more efficient, varying depending on the type of additive and production method. Similar observations were reported by [ 73 ] who modified biochar with sodium pyrophosphate and also recorded a higher yield of such a composite compared to raw biochar. The highest efficiency was observed when creating the BC2 composite from biochar impregnated with FFHCO2.…”

“…The higher ash content in the composites was caused by the additives used in the production of the composites. The results obtained by [ 73 ] indicate a higher ash content in biochar composites with the addition of copper compounds. BC1 and BC2 composites prepared with the addition of FFHCO2 were characterized by the highest ash content (78.36% and 49.76%, respectively).…”

The Removal of Phosphorus from Wastewater Using a Sewage Sludge Biochar: A Column Study

“…Due to its sustainability and low-cost benefits for treating wastewater containing heavy metals, sludge biochar has recently attracted much attention [24]. It has been demonstrated that producing biochar from sewage sludge enables the safe processing of sewage sludge while also yielding an affordable and long-lasting sorbent [25]. The sorbents derived from sewage sludge typically possess a relatively large specific surface area (100-200 m 2 /g) and developed microporosity [22].…”