Modified chicken manure biochar enhanced the adsorption for Cd2+ in aqueous and immobilization of Cd in contaminated agricultural soil.

Biochar is thought to be good sorbent for heavy metal and exploring ways to increase the efficiency of heavy metal adsorption by biochar is of great importance. Chicken manure biochar was modified with sulfur, hydroxyapatite and MnFe2O4 respectively. The properties and composition of the pristine and modified biochar was characterized. The pH and ash content of biochar was significantly increased after modification. Energy dispersive spectroscopy results showed that biochar modified with sulfur, hydroxyapatite and MnFe2O4 was successfully loaded on S, Ca/P and Fe/Mn respectively. The adsorption kinetic of Cd2+ absorption by pristine and modified biochar was better fitted by the pseudo second-order kinetic model, suggesting that the adsorption of Cd2+ on biochar followed the process of chemisorption. The Cd2+ adsorption isotherms of sulfur modified chicken manure biochar (SCMB), hydroxyapatite modified chicken manure biochar (HCMB) and MnFe2O4 modified chicken manure biochar (FMCMB) was better fitted by Freundlich model, while the Cd2+ adsorption by pristine chicken manure biochar (CMB) was well fitted by Langmuir model. The maximum Cd2+ adsorption capacity of SCMB, HCMB, FMCMB and CMB was 188.20, 111.53, 109.94 and 19.65 mg·g-1 respectively. Quantitative analysis of Cd2+ adsorption mechanism by biochar showed that the contribution of ion exchange for Cd2+ adsorption of CMB accounted for 58 %, while SCMB, HCMB and FMCMB decreased to only 12 %, 8 % and 4 % respectively. Meanwhile, the contribution of precipitation, complexion and metal-Cπ coordination for Cd2+ adsorption increased after modification. Pot experiment showed that application of SCMB significantly increased soil pH value, decreased the bioavailable Cd in soil and Cd uptake by brassica chinensis shoots, suggesting that SCMB can be a potential material for the safety use of Cd contaminated agricultural soil.

[Adsorption Capacity and Mechanism of Biochar Derived from Typical Agricultural Wastes for Cadmium in Aqueous Solutions].

Twelve biochar types were derived from animal manure (cow manure, chicken manure, and pig manure) and crop straw (wheat straw, rice straw, and corn straw) at different temperatures (300℃/700℃ and 300℃/500℃) for Cd2+ in a solution system in the present study. A scanning electron microscope, Fourier infrared spectrometer, X-ray diffraction, and CHN analyzer were applied to analyze the physical and chemical properties, surface structure, and elemental composition of the biochar. The adsorption capacity and related mechanism of biochar for Cd2+ in an aqueous solution was studied. The results showed that the maximum adsorption capacity of cow manure, chicken manure, and pig manure biochar for Cd2+ increased from 83.40, 19.65, and 96.74 mg·g-1 to 106.54, 268.89, and 164.53 mg·g-1, respectively, with the increase in pyrolysis temperature. With the increase in pyrolysis temperature, the pore structure of biochar became more abundant, oxygen-containing functional groups increased, and the aromatic structure appeared. Quantitative analyses revealed that ion exchange accounted for 12%-52%, chemical precipitation accounted for 27%-79%, complexation accounted for 1%-8%, and cation-π accounted for 1%-28% of the total adsorption capacity of Cd2+. With the increase in pyrolysis temperature, the proportion of cation-π interaction increased from 1%-13% to 8%-30%, but the proportion of chemical precipitation and ion exchange were still very high (70%-93%). Therefore, ion exchange and chemical precipitation could be the main mechanisms of agricultural waste biochar adsorption for Cd2+.

Stabilization of Zinc in Agricultural Soil Originated from Commercial Organic Fertilizer by Natural Zeolite.

Exploring ways to reduce the risk of heavy metal pollution by organic fertilizer application is of vital importance. In the present study, by conducting a pot experiment, natural zeolite was applied together with pig manure based organic fertilizer to agricultural soil in order to test its possibility of reducing the risk of heavy metals originating from pig manure. The results showed that a low rate of organic fertilizer (10%) application increased the biomass of Chinese cabbage (by 57.2%), while a high rate of organic fertilizer (30%) decreased the biomass of Chinese cabbage (by 46.16%), and meanwhile a 3% zeolite addition increased the biomass of Chinese cabbage which was treated with 30% organic fertilizer. The organic fertilizer addition decreased soil pH and increased soil CEC, while zeolite addition increased soil pH and decreased the soil organic matter content. The concentration of Zn in Chinese cabbage shoots increased with the organic fertilizer addition from 4.46% to 48.27%, while the addition of 1% and 3% zeolite significantly decreased Zn in Chinese cabbage shoots by 15.53% and 14.08%, respectively. The concentration of DPTA-extractable and DGT-extractable Zn of soil was increased by organic fertilizer application, whereas zeolite addition decreased the concentration of DPTA-extractable and DGT-extractable Zn in soil treated with organic fertilizer. Our present study suggests that natural zeolite application could be a promising method to reduce the risk of heavy metals originating from organic fertilizers.

Combination application of elemental sulfur and earthworm increased the lead (Pb) uptake by ryegrass (Lolium perenne L.) in contaminated agricultural soil.

The phytoremediation efficiency is largely depends on the bioavailability of heavy metal in soil. The activity of earthworms and oxidation of elemental sulfur (S0) in soil has influence on heavy metal speciation transformation in soil. By conducting pot experiment, we examined the possibility of enhancing phytoextraction efficiency of lead (Pb) in soil by ryegrass (Lolium perenne L.) with application of both S0 and earthworms. Results showed that the addition of S0 decreased soil pH and increased soil CEC, while a slight trend of decrease for soil pH and increase for CEC was found with earthworm application. In soil treated with earthworms, the addition of S0 increased the concentration of DTPA-extractable Pb by 9.9~20.8%. The concentration of diffusive gradients in thin film (DGT)-extractable Pb was increased by 26.31~32.9% with S0 and earthworm addition. In soil treated with earthworms, the addition of S0 increased the concentration of Pb in shoots of ryegrass by 55.7~110.4% and the translocation factor of Pb in ryegrass was also increased by S0 addition. Our results suggested that the combination application of earthworms and S0 could be an effective way to enhance the remediation efficiency of ryegrass for Pb-contaminated soil.

[Analysis and computational fluid dynamics simulation of hemodynamic influences caused by splenic vein thrombosis].

This paper aims to analyze the impact of splenic vein thrombosis (SVT) on the hemodynamic parameters in hepatic portal vein system. Based on computed tomography (CT) images of a patient with portal hypertension and commercial software MIMICS, the patient's portal venous system model was reconstructed. Color Doppler ultrasound method was used to measure the blood flow velocity in portal vein system and then the blood flow velocities were used as the inlet boundary conditions of simulation. By using the computational fluid dynamics (CFD) method, we simulated the changes of hemodynamic parameters in portal venous system with and without splenic vein thrombosis and analyzed the influence of physiological processes. The simulation results reproduced the blood flow process in portal venous system and the results showed that the splenic vein thrombosis caused serious impacts on hemodynamics. When blood flowed through the thrombosis, blood pressure reduced, flow velocity and wall shear stress increased. Flow resistance increased, blood flow velocity slowed down, the pressure gradient and wall shear stress distribution were more uniform in portal vein. The blood supply to liver decreased. Splenic vein thrombosis led to the possibility of forming new thrombosis in portal vein and surroundings.

CCR5 facilitates endothelial progenitor cell recruitment and promotes the stabilization of atherosclerotic plaques in ApoE-/- mice.

INTRODUCTION: Unstable atherosclerotic plaques are prone to rupture, which leads to atherothrombosis. Endothelial progenitor cells (EPCs) are bone marrow-derived precursor cells that may repair vascular injury in atherosclerosis. Chemokine (C-C motif) receptor 5 (CCR5) promotes mobilization of EPCs. In this study, we investigated the therapeutic potential of CCR5-overexpressing EPCs on plaque stabilization in an apolipoprotein E (ApoE)-/- mouse model. METHODS: The expression of CCR5 and its cognate ligand chemokine (C-C motif) ligand 5 (CCL5) was examined in atherosclerotic aortas of humans and mice by immunohistochemistry. Splenectomized ApoE-/- C57BL/6 J mice fed a high-fat diet for 24 weeks were intravenously injected with EPCs transfected with CCR5 overexpression lentivirus. The recruitment of EPCs over the atherosclerotic plaques was evaluated by immunofluorescence. The content of lipid, smooth muscle cells, monocytes/macrophages, and endothelial cells in atherosclerotic plaques was assayed by specific immunostaining. The serum levels of atherosclerosis-related inflammatory factors in ApoE-/- mice were measured by mouse atherosclerosis antibody array I. RESULTS: CCR5 and CCL5 are highly expressed in atherosclerotic plaques in both humans and mice. The ApoE-/- mice with CCR5-overexpressing EPC treatment demonstrated a more stable plaque formation with enhanced recruitment of EPC, reduced lipid, and macrophage content in the atherosclerotic plaques. CCR5-overexpressing EPC treatment also increased the content of endothelial cells and nitric oxide production in the plaques. In addition, the serum levels of interleukin-3 (IL-3), IL-5, IL-6, IL-13, CD40, and tumor necrosis factor-alpha and the plaque contents of IL-6 and matrix metalloproteinase-9 were reduced in mice with CCR5-overexpressing EPC treatment. CONCLUSIONS: These findings suggest that CCR5 is a novel therapeutic target in EPC treatment for stabilization of atherosclerotic plaques.