Influences of Temperature and Metal on Subcritical Hydrothermal Liquefaction of Hyperaccumulator: Implications for the Recycling of Hazardous Hyperaccumulators

Abstract

Waste Sedum plumbizincicola, a zinc (Zn) hyperaccumulator during phytoremediation, was recycled via a subcritical hydrothermal liquefaction (HTL) reaction into multiple streams of products, including hydrochar, bio-oil, and carboxylic acids. Results show approximately 90% of Zn was released from the S. plumbizincicola biomass during HTL at an optimized temperature of 220 °C, and the release risk was mitigated via HTL reaction for hydrochar production. The low-Zn hydrochar (∼200 mg/kg compared to original plant of 1558 mg/kg) was further upgraded into porous carbon (PC) with high porosity (930 m/g) and excellent capability of carbon dioxide (CO) capture (3 mmol/g). The porosity, micropore structure, and graphitization degree of PCs were manipulated by the thermal recalcitrance of hydrochar. More importantly, results showed that the released Zn could effectively promote the production of acetic acid via the oxidation of furfural (FF) and 5-(hydroxymethyl)-furfural (HMF). Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) with negative electrospray ionization analysis confirmed the deoxygenation and depolymerization reactions and the production of long chain fatty acids during HTL reaction of S. plumbizincicola. This work provides a new path for the recycling of waste hyperaccumulator biomass into value-added products.

Characterization of biofuel production from hydrothermal treatment of hyperaccumulator waste (Pteris vittata L.) in sub- and supercritical water

“…It has recently been reported that released metal ions such as nickel, zinc, copper and lead presented remarkable impact on the HTL reactions and could improve the bio-oil yield and promote product quality. 19,21,22 2.2 HTL procedure and analysis methods A schematic diagram of the experimental setup and procedure for the separation of the HTL products was shown in Fig. 1.…”

“…Research on HTL treatment of hyperaccumulator wastes have been carried out in recent years. [15][16][17][18][19] Clercq et al 16 investigated the HTL process of Pteris vittata L. under sub-and supercritical conditions and demonstrated that the main products in the liquid phase were ketones and phenols. Yang et al 17 employed hydrothermal process to obtain bio-oil and remove heavy metals from Pteris vittata L., and gained a bio-oil recovery efficiency of 83% with heavy metals removal efficiency of 99% under optimal condition.…”

“…Besides, it was reported that during hydrothermal liquefaction of waste Sedum plumbizincicola, the released zinc ions could effectively promote the generation of acetic acid. 19 Through these studies, it was found that hydrothermal liquefaction of hyperaccumulator wastes could result in a relatively high yield of bio-oil with higher caloric value. Meanwhile, the enriched heavy metals in the raw biomass could be converted to a stable state in the solid phase via HTL, which could be easily processed.…”

Biofuel Production Using Thermochemical Conversion of Heavy Metal-Contaminated Biomass (HMCB) Harvested from Phytoextraction Process

“…from feedstocks into the following processes and/or products, otherwise, the abovementioned contaminants could have poisoned the conversion/refinery catalysts or degraded the bio-products to some extent [93]. However, few studies have reported some positive effects of HMs on thermochemical processes, the yield and quality of biofuels in terms of the distribution of chemical components in the biofuels [94][95][96][97][98]. Therefore, to enhance the quality and quantity of desired biofuels, the biomass pretreatments are selected based on the biomass composition and its characteristics, the type of contaminants, and operating conditions [99,100].…”

A Review What Is Hydrothermal ?

“…Jadi larutan hydrothermal terbentuk pada bagian akhir dari siklus pembekuan magma(67; 68).Larutan hydrothermal terjadi dalam beberapa cara(121)(122). Salah satunya peleburan magma yang terjadi oleh parsial basah yang mendingin dan mengkristal, air yang menyebabkan peleburan parsial basah dilepaskan(69)(70)(71)(72)(73)(74)(75)(76)(77). Namun tidak sebagai air murni (123), tetapi mengandung semua unsur yang dapat larut yang terdapat pada magma seperti NaCl dan unsur kimia: emas, perak, tembaga, timbal, zinc, merkuri dan molybdenum, yang tidak terikat kuarsa, feldspar, dan mineral lain dengan substitusi ion(78; 79).…”