Influence of potassium addition on phosphorus availability and heavy metals immobility of biochar derived from swine manure.

Pyrolysis of animal manure at high temperature is necessary to effectively immobilize heavy metals, while the available phosphorus (P) level in biochar is relatively low, rendering it unsuitable for use as fertilizer. In this study, the pretreatment of swine manure with different potassium (K) sources (KOH, KCO, CHCOOK and CHKO) was conducted to produce a biochar with enhanced P availability and heavy metals immobility. The addition of all K compounds lowered the peak temperature of decomposition of cellulose in swine manure.

The interaction of different chlorine-based additives with swine manure during pyrolysis: Effects on biochar properties and heavy metal volatilization.

Poor properties and high concentrations of heavy metals are still major concerns of successful application of animal manure-derived biochar into the environment. This work thus proposed to add chlorine-based additives (Cl-additives, i.e.

Effect of Different Phosphates on Pyrolysis Temperature-Dependent Carbon Sequestration and Phosphorus Release Performance in Biochar.

Carbon sequestration is the primary function of biochar. Hence, it is necessary to design biochar with high carbon (C) retention and low C loss. In this study, three P compounds, including KHPO, Ca(HPO), and NHHPO, were premixed with corn stalk (1:4, /), aiming to produce biochars (CSB+K, CSB+Ca, and CSB+N) with high C sequestration and slow release of P at three temperatures (300, 500, and 700 °C).

Co-Pyrolysis of Cotton Stalks and Low-Density Polyethylene to Synthesize Biochar and Its Application in Pb(II) Removal.

It is inevitable that reclaimed cotton stalks will contain a certain amount of plastic film due to the wide application of plastic mulching during the process of cotton cultivation, and this makes it inappropriate to return it to the field or for it to be processed into silage. In this study, biochars were prepared by the co-pyrolysis of cotton stalk with low-density polyethylene (LDPE) in the proportions of 1:0, 3:1, 2:1, and 1:1 (/) at 400 °C, 450 °C, and 500 °C and maintaining them for 1 h. The effects of the co-pyrolysis of cotton stalk with LDPE on the properties of biochars (e.

Effects of added calcium-based additives on swine manure derived biochar characteristics and heavy metals immobilization.

Although pyrolysis is a promising way for treating animal manure, the application is restricted with some limitations of biochar. To improve the quality of biochar derived from swine manure and enhance the immobilization of heavy metals (Cu and Zn) in it, swine manure was mixed with four types of Ca-based additives (CaO, CaCO, Ca(OH), and Ca(HPO)) prior to pyrolysis at 300-700 °C. The thermogravimetric characteristics of swine manure were obviously influenced The addition of CaO, CaCO, and Ca(OH) during the whole decomposition process.

Influence of pyrolysis temperature on the properties and environmental safety of heavy metals in chicken manure-derived biochars.

Animal manures usually contain high contents of heavy metals (HMs) and thus pose a considerable threat to human health and environment when applied to soil. In this study, the effect of pyrolysis temperature (300 °C, 400 °C, 500 °C, 600 °C, and 700 °C) on the properties of biochar produced from chicken manure was studied. In addition, the response of speciation, bioavailability, leachability, and environmental risk of HMs in biochar to different pyrolysis temperature was investigated.

Enhanced removal of hexavalent chromium by different acid-modified biochar derived from corn straw: behavior and mechanism.

It is of great significance to remove Cr(VI) from water as a result of its high toxicity. Biochar from corn straw was modified by different acids (HNO, HSO and HPO) to remove Cr(VI) from aqueous solution. To estimate the removal mechanisms of Cr(VI) by the acid-modified biochars, batch experiments were performed in the light of contact time, Cr(VI) concentration, and pH, and the characteristics of acid-modified biochars before and after Cr(VI) adsorption were investigated by Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS).

Influence of sodium hydroxide addition on characteristics and environmental risk of heavy metals in biochars derived from swine manure.

In order to improve characteristics of biochar, especially enhance immobilization of heavy metals in biochar, swine manure was pyrolyzed at low pyrolysis temperature (300 °C, 400 °C and 500 °C) with different amounts of sodium hydroxide (NaOH) added (0.5% and 2%, W/W). Results showed that NaOH addition during pyrolysis increased the pH, EC, ash content, yield rate, aromaticity and hydrophily, but did not increase surface area and porosity of resultant biochars.

A further inquiry into co-pyrolysis of straws with manures for heavy metal immobilization in manure-derived biochars.

Co-pyrolysis of straws with manures has been found effective to mitigate heavy metal risks in manure-derived biochars. This study further investigated co-pyrolysis strategy on the levels, species and risks of metals (Cu, Zn, Cr, Ni, Pb, and Cd) carried by manure-based biochars through co-pyrolyzing swine manure (SM) and corn straw (CS) with different mixture ratios (1:0, 0:1, 3:1, 1:1, and 1:3, w/w) at 300 ℃, 500 ℃ and 700 ℃. The total heavy metals in SM biochars were significantly reduced by CS addition except when SM/CS ratio was 3:1 at 300 ℃.