Abstract:The biochar derived from the dreadful weed water hyacinth (Eichhornia crassipes) was activated with phosphoric acid was utilized for adsorption of hexavalent chromium (Cr (VI)) from the simulated solution. The characterization (Zeta potential, specific surface area, Scanning Electron Microscope analysis) of biochar was done to study the surface properties of the biochar. The modified biochar (379 m2g-1) recorded 49.80% greater surface area in comparison to the pristine biochar (253 m2g-1). Zeta potential of mo… Show more
“…The predominant species observed in this solution is Cr 2 O 7 2− and HCrO 4 − as the pH is 2 [9]. Kalaiarasi et al [37] found that maximum Cr removal (90 %) is removed at pH 2, as lower pH influences biochar surface and promotes Cr adsorption. Similarly, Bedada et al [4] discovered that the Cr removal capacity of the adsorbent reduced by 10.3 % as the pH of the solution rose from 2 to 6.…”
Section: Phmentioning
confidence: 83%
“…The pore volume is 0.12 cc g −1 , and the pore radius is 32.82 Å. The pore radius revealed mesopores (2–50 nm) as per the International Union of Pure and Applied Chemistry [31, 32, 37]. The BET study demonstrates that ZJSAB, with its surface area, pore volumes, and pore size, provides multiple active sites for Cr(VI) adsorption.…”
Section: Resultsmentioning
confidence: 99%
“…Kalaiarasi et al. [37] found that maximum Cr removal (90 %) is removed at pH 2, as lower pH influences biochar surface and promotes Cr adsorption. Similarly, Bedada et al.…”
The present study aims to remove chromium (Cr) from a synthetic solution using Ziziphus jujube seed (ZJS)‐activated biochar (ZJSAB) as an adsorbent. Physicochemical characterization was carried out to understand the properties of ZJSAB samples. Adsorption characteristics of ZJSAB were determined using batch experiments for various temperatures, pH, dosage, concentration, and duration. The study reveals ZJSAB has 93 % efficiency in the removal of Cr for an initial concentration of 60 mg L−1 at 30 °C and 2 pH with 0.6 g L−1 dosage and 120 min duration. Freundlich isotherm and pseudo‐second‐order models were best fit with maximum removal efficiency for ZJSAB. When 0.3 N hydrochloric acid was introduced to a desorption study, Cr desorption was 93.47 %. The study reveals that activated biochar from ZJS was efficient for Cr removal from aqueous solutions.
“…The predominant species observed in this solution is Cr 2 O 7 2− and HCrO 4 − as the pH is 2 [9]. Kalaiarasi et al [37] found that maximum Cr removal (90 %) is removed at pH 2, as lower pH influences biochar surface and promotes Cr adsorption. Similarly, Bedada et al [4] discovered that the Cr removal capacity of the adsorbent reduced by 10.3 % as the pH of the solution rose from 2 to 6.…”
Section: Phmentioning
confidence: 83%
“…The pore volume is 0.12 cc g −1 , and the pore radius is 32.82 Å. The pore radius revealed mesopores (2–50 nm) as per the International Union of Pure and Applied Chemistry [31, 32, 37]. The BET study demonstrates that ZJSAB, with its surface area, pore volumes, and pore size, provides multiple active sites for Cr(VI) adsorption.…”
Section: Resultsmentioning
confidence: 99%
“…Kalaiarasi et al. [37] found that maximum Cr removal (90 %) is removed at pH 2, as lower pH influences biochar surface and promotes Cr adsorption. Similarly, Bedada et al.…”
The present study aims to remove chromium (Cr) from a synthetic solution using Ziziphus jujube seed (ZJS)‐activated biochar (ZJSAB) as an adsorbent. Physicochemical characterization was carried out to understand the properties of ZJSAB samples. Adsorption characteristics of ZJSAB were determined using batch experiments for various temperatures, pH, dosage, concentration, and duration. The study reveals ZJSAB has 93 % efficiency in the removal of Cr for an initial concentration of 60 mg L−1 at 30 °C and 2 pH with 0.6 g L−1 dosage and 120 min duration. Freundlich isotherm and pseudo‐second‐order models were best fit with maximum removal efficiency for ZJSAB. When 0.3 N hydrochloric acid was introduced to a desorption study, Cr desorption was 93.47 %. The study reveals that activated biochar from ZJS was efficient for Cr removal from aqueous solutions.
“…The restricted adsorption sites could become saturated after being fully occupied by the adsorbed Pb(II) [ 49 ]. The adsorbent was exhausted and could no longer adsorb excess lead cations available in the solution [ 52 ]. Fig.…”
“…For instance, sulfuric acid and nitric acid treatments worked well to enhance the carboxyl and nitro functional groups of biochar [139]. H 3 PO 4 may break down aromatic and aliphatic biomass structures and form phosphate/polyphosphate cross bridges that prevent contraction and shrinkage during the pore-forming process [140]. Phosphate-containing compounds have been extensively employed in recent years to remove poisonous metals from soil and aquatic ecosystems [141].…”
Soil contamination through heavy metals (HMs) is a serious environmental problem that needs to be addressed. One of the methods of remediating soils contaminated with HMs and reducing the environmental risks associated with them is to immobilize these HMs in the soil using specific amendment(s). The use of biochar as an organic amendment can be an environmentally friendly and practically feasible option, as (i) different types of biomass can be used for biochar production, which contributes to environmental sustainability, and (ii) the functionality of biochar can be improved, enabling efficient immobilization of HMs. Effective use of biochar to immobilize HMs in soil often requires modification of pristine biochar. There are various physical, chemical, and biological methods for modifying biochar that can be used at different stages of pyrolysis, i.e., before pyrolysis, during pyrolysis, and after pyrolysis. Such methods are still being intensively developed by testing different modification approaches in single or hybrid systems and investigating their effects on the immobilization of HMs in the soil and on the properties of the remediated soil. In general, there is more information on biochar modification and its performance in HM immobilization with physical and chemical methods than with microbial methods. This review provides an overview of the main biochar modification strategies related to the pyrolysis process. In addition, recent advances in biochar modification using physical and chemical methods, biochar-based composites, and biochar modified with HM-tolerant microorganisms are presented, including the effects of these methods on biochar properties and the immobilization of HMs in soil. Since modified biochar can have some negative effects, these issues are also addressed. Finally, future directions for modified biochar research are suggested in terms of scope, scale, timeframe, and risk assessment. This review aims to popularize the in situ immobilization of HMs with modified biochar.
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