Comparison of nickel adsorption on biochars produced from mixed softwood and Miscanthus straw

Abstract

In order to understand the influence of feedstock type on biochar adsorption of heavy metals, the adsorption characteristics of nickel (Ni), copper (Cu) and lead (Pb) onto biochars derived from mixed softwood and Miscanthus straw were compared. The biochars were produced from mixed softwood pellets (SWP) and Miscanthus straw pellets (MSP), at both 550 and 700 °C for each material, using a standardised production procedure recommended by the UK Biochar Research Centre. Kinetics analyses show that the adsorption of Ni to all four biochars reached equilibrium within 5 min. The degree of Ni removal for all four biochars remained nearly constant within initial pH values of 3-8, because the equilibrium pH values within this range were similar due to the buffering effect of the biochars. A sharp increase of Ni removal percentage for all biochars at initial solution pH 8-10 was observed as the equilibrium pH also increased. MSP derived biochars generally had higher maximum adsorption capacities (Q) for the three tested metals as compared with those from SWP, which was likely due to their higher degree of carbonisation during production. This study shows that feedstock type is a primary factor affecting the adsorption capacities of the tested biochars for heavy metals.

Highly efficient nickel (II) removal by sewage sludge biochar supported α-Fe2O3 and α-FeOOH: Sorption characteristics and mechanisms

“…However, the dominant role was proved to be chemical adsorption rather than physical adsorption based on our kinetic study. Similar results were reported in other Ni(II) adsorption studies [47]. Furthermore, the adsorption isotherm analysis revealed monolayer sorption on a homogeneous sorption surface could be dominant in the experiments.…”

“…The initial rapid adsorption phenomenon could be attribute to electrostatic attraction and ion exchange, and chemical adsorption acted as a crucial role in the following step [14]. The chemical reactions of heavy metal adsorption were generally defined as inner-sphere complexation and co-precipitation [47]. The solution after Ni(II) adsorption was detected by ICP-AES and K + , Mg 2+ and Ca 2+ were found after the adsorption treatment, convincingly demonstrating the ion exchange between Ni(II) and aforementioned metal ions.…”

Enhanced activation of ultrasonic pre-treated softwood biochar for efficient heavy metal removal from water

“…Nevertheless, pseudo second order kinetics fitted well with the experimental data, with R 2 > 0.9934. This elucidates chemisorption as the rate limiting mechanism, mostly ion exchange interactions which are generally rapid reactions (Shen et al 2018). The results represented in Table 3 shows that ultrasound pre-treated biochars have higher equilibrium adsorption capacity (Qe) after activation, when compared with ultrasound untreated sample.…”

“…Due to the heterogeneity and feedstock dependency for physicochemical properties, mix-wood chips are rarely used for adsorption studies, therefore comparable studies available for activation and adsorption using biochar derived from mixed softwood is limited (Chen et al, 2011;Shen et al, 2018;Tomczyk et al, 2020). To the best of our knowledge, this is the first ever study focusing on the effect of combination of alkali activation towards power ultrasound pre-treated mix-wood biochar and study its heavy metal removal efficiency from water.…”

Spectroscopic and Modeling Investigation of Sorption of Pb(II) to ZSM-5 Zeolites

“…Heavy metals that are released into the environment are a major public health concern due to their toxic nature and persistence, and lead (Pb) is among the most common. − A wide range of remediation methods have been investigated to remove heavy metals from water and wastewater, including surface precipitation, ion exchange, electrochemical processes, adsorption, , and a combination of these methods . Of the methods described above, adsorption is considered to be an efficient and economic method of metal remediation, and zeolites are some of the most widely used and low-cost adsorbents .…”