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Nowadays, the residual heavy metals and antibiotics in water and soil have a potential threat to human being health, thereby their purification is of great importance. In this study, the application of Cr6+ and chlortetracycline (CTC) removal using a new fruit peel based biochar composite (FPBC) had been explored. Batch experiments results showed that FPBC presented excellent removal performance on Cr6+ and CTC, and the simultaneous removal efficiencies of Cr6+ and CTC were 97% and 81% within 180 min, respectively. The adsorption kinetics and isotherms of Cr6+ by FPBC could be well described by the pseudo-second-order and Langmuir models, respectively, and its adsorption was a spontaneous endothermic process. The inhibitory of the coexisting anions on Cr6+ removal of followed the order of HPO 4 3-> HCO 3 -> SO 4 2->NO 3 -> Cl-. The simultaneous removal of Cr6+ and CTC by FPBC had been achieved at low CTC content levels. The presence of NaCl showed a significant inhibitory on Cr6+ removal but a positive effect on CTC removal at low content level. A potential reaction mechanism of both Cr6+ and CTC removal over FPBC was proposed on the basic of the comprehensive characterizations and adsorption performance. Both reduction and surface precipitation reactions might be dominant in Cr6+ removal process, whereas both complexation and hydrogen bond interaction might be mainly responsible for CTC removal. These findings suggested that this fruit peel based biochar composite might be a promising material for the remediation of Cr6+ and CTC-contaminated wastewater. [Display omitted] • A new fruit peel based biochar composite (FPBC) was firstly synthesized. • Cr6+ adsorption was well described by pseudo-second-order and Langmuir models. • NaCl showed an inhibitory on Cr6+ removal but a positive effect on CTC removal. • FPBC presented a high simultaneous removal of Cr6+ and CTC. • A potential mechanism for Cr6+ and CTC removal over FPBC was proposed. [ABSTRACT FROM AUTHOR]

Recently, a large number of agricultural wastes have been extensively converted into biochar based materials, these biochar materials have been popularly employed in the removal of various pollutants from environment. Herein, a novel pigeon waste based biochar composite (FeBC) was firstly synthesized and applied for hexavalent chromium (Cr(VI)) and p-nitrophenol (PNP) adsorption in water. The most relevant findings showed that FeBC exhibited a superior performance on Cr(VI) and PNP adsorption compared with pristine biochar. The Cr(VI) monolayer adsorption onto FeBC might be dominant, and Cr(VI) adsorption by FeBC was an endothermic process. Both Cr(VI) and PNP adsorption behavior were well fitted with the pseudo-second-order kinetic model, Elovich, intra-particle diffusion (IPD), liquid film diffusion kinetic (LFD) and chemical reaction models. Both the pathway of PNP degradation and mechanism for Cr(VI) and PNP adsorption over FeBC were proposed. Almost half of Cr(VI) was reduced into Cr 2 O 3 and Cr(OH) 3 , both reduction and precipitation reactions might be dominant in Cr(VI) adsorption. O 2 •−, 1 O 2 and •OH were involved in PNP removal reaction, but the contribution of •OH was small. The oxidation, π-π interaction and hydrogen bonds interactions might be involved in this PNP removal process, and PNP was oxidized to form several intermediates via hydroxylation and ring cleavage reactions. This study could provide a novel treatment strategy for the simultaneous decontamination of effluents combined with heavy metals and organic compounds in realistic remediation application. [Display omitted] • A novel pigeon waste based biochar composite (FeBC) was firstly synthesized. • Almost half of Cr(VI) species were reduced into Cr 2 O 3 and Cr(OH) 3. • O 2 •−, 1 O 2 and •OH were involved in p-nitrophenol removal reaction. • Both Cr(VI) and p-nitrophenol removal were successfully achieved by FeBC. • A mechanism for the removal of Cr(VI) and p-nitrophenol was proposed. [ABSTRACT FROM AUTHOR]

• A synergistic effect between BC/PMS and nZVI/PMS processes has been achieved. • ATZ removal of BC-nZVI/PMS was higher than that of BC-nZVI/H 2 O 2 or BC-nZVI/PS. • SO 4 − was the predominant radical species responsible for ATZ degradation. • ATZ was degraded through de-alkylation, dechlorination and hydroxylation processes. • A reaction mechanism of PMS activation by BC-nZVI for ATZ degradation was proposed. Over the past decade, herbicides contaminated soil poses a serious threat to humans and environment. In this study, a novel biochar supported zero valent iron (BC-nZVI) was used as a heterogeneous catalyst activating peroxymonosulfate (PMS) for the removal of herbicide atrazine (ATZ) from soil. The results revealed that the removal of ATZ by BC-nZVI/PMS process was superior to that of BC/PMS or nZVI/PMS process. A synergistic effect between BC/PMS and nZVI/PMS processes has been successfully achieved in BC-nZVI/PMS process, and nearly 96% of ATZ removal was obtained at optimum reaction conditions. BC-nZVI/PMS process exhibited an excellent performace on ATZ removal compared with BC-nZVI/H 2 O 2 or BC-nZVI/persulfate (PS) process. PMS decomposition by BC-nZVI/PMS process was higher than the sum of BC/PMS and nZVI/PMS processes. A low Cu concentration accelerated ATZ removal, and Cu was also effectively immobilized. SO 4 − was the predominant reactive oxygen species responsible for ATZ degradation, and OH and 1O 2 also took part in reaction. Four kinds of ATZ degradation products were identified, and ATZ degradation could be achieved through de-alkylation, dechlorination and hydroxylation processes. A reaction mechanism of PMS activation by BC-nZVI was proposed based on the synergistic effect of BC and nZVI. In addition to ATZ, coexisting pollutants such as 2,4-dichlorophenol (2,4-DCP), Cu and Cd were also simultaneously removed from soil. [ABSTRACT FROM AUTHOR]

• Immobilization of metals by BC-nZVI process was superior to that of BC or nZVI. • Immobilization of Cd or Pb was inhibited with addition of 2,4-dichlorophenol. • Cd and Pb availability decreased, whereas soil pH and organic matter increased. • Stable metals speices such as CdCO 3 , Cd(OH) 2 , PbCO 3 and Pb(OH) 2 were formed. • Mechanism for the simultaneous immobilization of Cd and Pb in soil was proposed. Risk associated with heavy metals in soil has been received widespread attention. In this study, a porous biochar supported nanoscale zero-valent iron (BC-nZVI) was applied to immobilize cadmium (Cd) and lead (Pb) in clayey soil. Experiment results indicated that the immobilization of Cd or Pb by BC-nZVI process was better than that of BC or nZVI process, and about 80% of heavy metals immobilization was obtained in BC-nZVI process. Addition of BC-nZVI could increase soil pH and organic matter (SOM). Cd or Pb immobilization was inhibited with coexisting organic compound 2,4-dichlorophenol (2,4-DCP), but 2,4-DCP could be removed in a simultaneous manner with Cd or Pb immobilization at low concentration levels. Simultaneous immobilization of Cd and Pb was achieved in BC-nZVI process, and both Cd and Pb availability significantly decreased. Stable Cd species inculding Cd(OH) 2 , CdCO 3 and CdO were formed, whereas stable Pb species such as PbCO 3 , PbO and Pb(OH) 2 were produced with BC-nZVI treatment. Simultaneous immobilization mechanism of Cd and Pb in soil by BC-nZVI was thereby proposed. This study well demonstrates that BC-nZVI has been emerged as a potential technology for the remediation of multiple heavy metals in soil. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] Nowadays, the harm of antibiotics residues in environments to human health and ecological safety has been causing more and more attention. In this paper, a biochar based iron material (MBC) was used to activate persulfate (PS) for the removal of sulfadiazine (SDZ) from aqueous solution. Experiment results indicate that the degradation and mineralization of SDZ by MBC/PS system reached 91.79% and 60% within 60 min under the optimal reaction conditions, respectively. MBC/PS system exhibited a better performance on SDZ removal compared with MBC/H 2 O 2 system. The addition of Cu2+ ion could enhance the degradation of SDZ by MBC/PS system. PO 4 3-, Cl- and SO 4 2- had a certain degree of inhibitory effect on the SDZ degradation. Both radicals and non-radical species such as SO 4 •-, •OH and 1O 2 participated in the degradation reaction of SDZ by MBC/PS system, but •OH was the main radical species responsible for SDZ degradation. The liquid chromatograph-mass spectrometer (LC-MS) technique was used to identify the intermediate products of SDZ, and it was proposed that the degradation of SDZ might be achieved through hydrolyzation, hydroxylation, deamination and amino-oxidization processes. A possible reaction mechanism involving a synergistic effect between PS homogeneous and heterogeneous activation processes as well as both radicals and non-radicals reactions was finally proposed. [ABSTRACT FROM AUTHOR]

The pollution of heavy metals and organic compounds has received increased attention in recent years. In the current study, a novel biochar-based iron oxide composite (FeYBC) was successfully synthesized using pomelo peel and ferric chloride solution through one-step process at moderate temperature. Results clearly demonstrate that FeYBC exhibited more efficient removal of Cr(VI) and/or phenol compared with the pristine biochar, and the maximum adsorption amounts of Cr(VI) and phenol by FeYBC could reach 24.37 and 39.32 mg g−1, respectively. A series of characterization data suggests that several iron oxides such as Fe 2 O 3 , Fe0, FeOOH and Fe 3 O 4 were formed on the FeYBC surface as well as oxygen-containing groups. Thermodynamics study indicates that Cr(VI) and phenol adsorption by FeYBC were endothermic and exothermic processes, respectively. Langmuir adsorption isotherm and pseudo-second order models could better explain the Cr(VI) and phenol adsorption behaviors over FeYBC. The Cr(VI) adsorption might be primarily achieved through the ion exchange and surface complexation and reduction, whereas the π–π interaction and electron donor–acceptor complex mainly contributed to phenol adsorption. The findings indicate that the biochar-based iron oxide composites material was an efficient adsorbent for the remediation of industrial effluents containing Cr(VI) and phenol. [Display omitted] • A novel biochar-based iron oxide composite (FeYBC) was firstly synthesized. • FeYBC exhibited more efficient Cr(VI) and phenol removal than pristine biochar. • Langmuir and pseudo second order models well explain Cr(VI) and phenol adsorption. • Cr(VI) and phenol adsorption were endothermic and exothermic nature, respectively. • The possible removal mechanism of both Cr(VI) and phenol adsorption was proposed. [ABSTRACT FROM AUTHOR]