Dual‑Doped Nickel Sulfide for Electro‑Upgrading Polyethylene Terephthalate into Valuable Chemicals and Hydrogen Fuel

Electro-upcycling of plastic waste into value-added chemicals/fuels is an attractive and sustainable way for plastic waste management.Recently,electrocatalytically converting polyethylene terephthalate(PET)into formate and hydrogen has aroused great interest,while developing low-cost catalysts with high efficiency and selectivity for the central ethylene glycol(PET monomer)oxidation reaction(EGOR)remains a challenge.Herein,a high-performance nickel sulfide catalyst for plastic waste electro-upcycling is designed by a cobalt and chloride co-doping strategy.Benefiting from the interconnected ultrathin nanosheet architecture,dual dopants induced upshifting d band centre and facilitated in situ structural reconstruction,the Co and Cl co-doped Ni_(3)S_(2)(Co,Cl-NiS)outperforms the singledoped and undoped analogues for EGOR.The self-evolved sulfide@oxyhydroxide heterostructure catalyzes EG-to-formate conversion with high Faradic efficiency(>92%)and selectivity(>91%)at high current densities(>400 mA cm^(−2)).Besides producing formate,the bifunctional Co,Cl-NiS-assisted PET hydrolysate electrolyzer can achieve a high hydrogen production rate of 50.26 mmol h^(−1)in 2 M KOH,at 1.7 V.This study not only demonstrates a dual-doping strategy to engineer cost-effective bifunctional catalysts for electrochemical conversion processes,but also provides a green and sustainable way for plastic waste upcycling and simultaneous energy-saving hydrogen production.

Gasification of Organic Waste:Parameters,Mechanism and Prediction with the Machine Learning Approach

Gasification of organic waste represents one of the most effective valorization pathways for renewable energy and resources recovery,while this process can be affected by multi-factors like temperature,feedstock,and steam content,making the product’s prediction problematic.With the popularization and promotion of artificial intelligence such as machine learning(ML),traditional artificial neural networks have been paid more attention by researchers from the data science field,which provides scientific and engineering communities with flexible and rapid prediction frameworks in the field of organic waste gasification.In this work,critical parameters including temperature,steam ratio,and feedstock during gasification of organic waste were reviewed in three scenarios including steam gasification,air gasification,and oxygen-riched gasification,and the product distribution and involved mechanism were elaborated.Moreover,we presented the details of ML methods like regression analysis,artificial neural networks,decision trees,and related methods,which are expected to revolutionize data analysis and modeling of the gasification of organic waste.Typical outputs including the syngas yield,composition,and HHVs were discussed with a better understanding of the gasification process and ML application.This review focused on the combination of gasification and ML,and it is of immediate significance for the resource and energy utilization of organic waste.

Three-Dimensional Simulation of Hydrodynamic Mechanism of Fluidized Bed Methanation

Organic solid waste(OSW)contains many renewable materials.The pyrolysis and gasification of OSW can realize resource utilization,and its products can be used for methanation reaction to produce synthetic natural gas in the specific reactor.In order to understand the dynamic characteristics of the reactor,a three-dimensional numerical model has been established by the method of Computational Fluid Dynamics(CFD).Along the height of the reactor,the particle distribution in the bed becomes thinner and the mean solid volume fraction decreases from 4.18%to 0.37%.Meanwhile,the pressure fluctuation range decreased from 398.76 Pa at the entrance to a much lower value of 74.47 Pa at the exit.In this simulation,three parameters of gas inlet velocity,operating temperature and solid particle diameter are changed to explore their influences on gas-solid multiphase flow.The results show that gas velocity has a great influence on particle distribution.When the gas inlet velocity decreases from 6.51 to 1.98 m/s,the minimum height that particles can reach decreases from 169 to 100 mm.Additionally,as the operating temperature increases,the particle holdup inside the reactor changes from 0.843%to 0.700%.This indicates that the particle residence time reduces,which is not conducive to the follow-up reaction.Moreover,with the increase of particle size,the fluctuation range of the pressure at the bottom of the reactor increases,and its standard deviation increases from 55.34 to 1266.37 Pa.

Spatio-Temporal Characteristics of Heat Transfer of Methanation in Fluidized Bed for Pyrolysis and Gasification Syngas of Organic Solid Waste

Methanation is an effective way to efficiently utilize product gas generated from the pyrolysis and gasification of organic solid wastes.To deeply study the heat transfer and mass transfer mechanisms in the reactor,a successful three-dimensional comprehensive model has been established.Multiphase flow behavior and heat transfer mechanisms were investigated under reference working conditions.Temperature is determined by the heat release of the reaction and the heat transfer of the gas-solid flow.The maximum temperature can reach 951 K where the catalyst gathers.In the simulation,changes in the gas inlet velocity and catalyst flow rate were made to explore their effects on CO conversion rate and temperature for optimization purposes.As the inlet gas velocity increases from 2.78 to 4.79 m/s,the CO conversion rate decreases from 81.6%to 72.4%.However,more heat is removed from the reactor,and the temperature rise increases from 78.03 to 113.49 K.When the catalyst flow rate is increased from 7.18 to 17.96 kg/(m^(2)·s),the mass of the catalyst in the reactor is increased from 0.0019 to 0.0042 kg,and the CO conversion rate is increased from 66.8%to 81.5%.However,this increases the maximum temperature in the reactor from 940.0 to 966.4 K.

Synergistic Treatment of Low-concentration Organic Waste Gas by Micro-nano Bubble Coordinated with Peroxymonosulfate

Continuous dynamic experiment was conducted for the treatment of low-concentration organic waste gas with xylene as a representative, using micro-nano bubble and peroxymonosulfate working in synergy. The degradation rule of xylene under different conditions such as the ORP value of the spray liquid, pH value of the spray liquid, liquid-gas ratio of the spray liquid, residence time of xylene, and initial concentration of xylene was investigated. The results showed that at a low concentration, the pH value of the spray liquid had little effect on the degradation rate of xylene. The degradation rate of xylene rose with the increase of the ORP value of the spray liquid, the liquid-gas ratio of the spray liquid, the residence time of xylene, and the initial concentration of xylene.

The Performance of Black Soldier Fly Larvae (BSFLs), Hermetia illucens L. (Diptera: Stratiomyidae), as a Function of the Substrate Used: A Review

Organic wastes are one of the greatest challenges that cities face worldwide. In numerous underdeveloped nations, like Cameroon, waste is often disposed of through landfills, composting, or open-air combustion. Unfortunately, the concept of waste sorting and organic waste processing is new to many individuals. This has led to an increase in the amount of organic waste and the costs connected with its management. Consequently, the majority of developing nations have sought out waste management solutions that are more cost-effective. Therefore, it has been determined that the bioconversion of organic wastes by black soldier fly larvae (BSFLs) (Hermetia illucens) into multifunctional prepupae is a viable alternative. Appreciation is given to the employment of the organic waste management approach in developing nations since it is not only environmentally friendly and economically viable, but also provides a means for waste valorisation through the production of diverse resources and potential economic benefits. Studies have proved the usefulness of the insect in controlling organic wastes, but countries such as Cameroon are still unfamiliar with the nuances of this method. Consequently, this timely review examined the performance of the BSFL, specifically in organic waste treatment, as well as the best practices for multiplying them to determine its viability for use in a waste treatment plant, the production of high-quality larvae as a source of protein for livestock, and the production of diesel fuel.

Influence of Stand-Alone Vertical Gas Vents on Aeration and Denitrification of Organic Municipal Waste Assessed by Two-Dimensional (2D) Lysimeters

Landfilled organic waste, in the presence of oxygen, can undergo aerobic decomposition facilitated by heterotrophic microorganisms. Aerobic degradation of solid waste can quickly consume available oxygen thus curtailing further degradation. The aim of this study was the investigation of a low-cost method of replenishing oxygen consumed in landfilled waste. Three 2D lysimeters were established to investigate the effectiveness of stand-alone, vertical ventilation pipes inserted into waste masses. Two different configurations of ventilation were tested with the third lysimeter acting as an unventilated control. Lysimeters were left uninsulated and observed over the course of 6 months with regular collection of gas and leachate samples. Lysimeters were then simulated for Oxygen (O2) and Nitrous oxide (N2O) to analyze the denitrification contributions of each. The experiment revealed that a single ventilation pipe can increase the mean oxygen level of a 1.7 m × 1.0 m area by up to 13.5%. It also identified that while increasing the density of ventilation pipes led to increased O2 levels, this increase was not significant at the 0.05 probability level. A single vent averaged 13.67% O2 while inclusion of an additional vent in the same area only increased the average to 14.59%, a 6.7% increase. Simulation helped to verify that lower ventilation pipe placement density may be more efficient as in addition to the effect on oxygenation, denitrification efficiency may increase. Simulations of N2O production estimated between 8% - 20% more N2O being generated with lower venting density configurations.

Research Advances in Agricultural Reutilization of Urban-rural Organic Wastes

The author summarized the advantages and potential risks of urban-rural organic wastes agricultural reutilization to reduce the potential risks of urban-rural organic wastes agricultural utilization. The results showed that： the organic wastes generated in urban-rural life as fertilizer applied into farmland made an impact on soil properties, then indirectly affected the soil microbial biomass and soil enzymes activities. In addition, the heavy metals in organic wastes would accumulate in the soil and damage to soil environment. Therefore, it was necessary to make a long- term research on the environment of soil which agricultural utilized of wastes.

Effects of Substrates before and after Fermenting Treatment on the Growth,Development and Cut Flower Quality of Lily

[Objective] The aim of this study was to explore the effects of substrates before and after fermenting treatment on the growth,development and cut flower quality of lily.[Method] Oriental lily cultivar ＇Siberia＇ was taken as material to study the effect of using fermentative and unfermented agricultural waste as substrates on the growth,development and cut flower quality of lily.And the physical and chemical properties of substrates before and after fermenting treatment were studied.[Result] The full decomposition of agricultural waste would greatly improve the physical and chemical properties of substrates,such as the fermentative substrates changed to stabilization,the ratio of carbon nitrogen had dropped drastically,the total porosity was increase,the ratio of gas and water was better,and the nutrition elements was increased.Moreover,it could significantly increased the plant height,stem diameter,leaf number,leaf area,leaf fresh weight and so on,as well as expanded the lily roots and significantly improved the rate of cut flower and cut flower quality.[Conclusion] This study had provided theoretically basis for the cultivation of cut lily.

Stable Control of Influence Factor during Two-phase Anaerobic Digestion for Agricultural Organic Waste

Two-phase anaerobic digestion process is influenced by acid control for hydrogen production, reaction temperature, substrate detention time, sludge activity, and granular formation. Al of these technological parameters are directly related to success or failure of the system operation and treatment effect.

Screening on oil-decomposing microorganisms and application in organic waste treatment machine

As an oil-decomposable mixture of two bacteria strains(Bacillus sp. and Pseudomonas sp.), Y3 was isolated after 50 d domestication under the condition that oil was used as the limited carbon source. The decomposing rate by Y3 was higher than that by each separate individual strain, indicating a synergistic effect of the two bacteria. Under the conditions that T=25—40℃,pH=6—8, HRT(Hydraulic retention time)=36 h and the oil concentration at 0.1%, Y3 yielded the highest decomposing rate of 95.7 %. Y3 was also applied in an organic waste treatment machine and a certain rate of activated bacteria was put into the stuffing. A series of tests including humidity, pH, temperature, C/N rate and oil percentage of the stuffing were carried out to check the efficacy of oil-decomposition. Results showed that the oil content of the stuffing with inoculums was only half of that of the control. Furthermore, the bacteria were also beneficial to maintain the stability of the machine operating. Therefore, the bacteria mixture as well as the machines in this study could be very useful for waste treatment.

Pyrolysis of rice husk and sawdust for liquid fuel

The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465 ℃, 61% at 490℃ and 60% at 475℃ respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.

Study on the Recovery of Rhodium from Spent Organic Rhodium Catalysts of Acetic Acid Industry Using Pyrometallurgical Process

A new process recycling rhodium from organic waste containing rhodium in acetic acid industry is developed. Use the special affinity of base metal sulfides (FeS, Ni2S3 , CuS, etc.) on platinum group metals, adopting high nickel matte trapping-aluminothermic activation method to recovery rhodium from incinerator residue of organic rhodium waste. The method is shorter process, lower equipment requirement, and the higher activity of rhodium black. In pyrometallurgy enrichment process,the recovery rate of rhodium reached 94.65%, the full flow of rhodium recovery rate was 92.04%.

Conversion of organic carbon in the decomposable organic wastes in anaerobic lysimeters under different temperatures

The quantitative fractions of conversion of organic carbon in the decomposable organic wastes with initial moisture of 70% sorted from municipal solid wastes(MSW) in lysimeters into biogas, leachate and solid residue were characterized, under temperatures of 25, 30 and 41℃, respectively, and circulation of leachate generated within the lysimeters. It is found that 27% of organic carbon in the wastes are conversed into gases, 0.8% into leachate, and the other 72% remained in the decomposable solid residues, after 180 days' degradation at 41℃. Higher temperature will lead to more rapid degradation and result to higher conversion of the organic carbon to biogas and lower to both solid residues and leachate, while the pollutant concentrations in leachate will be lower at a higher temperature and the values of COD are quite consistent with TOC.

Effective incineration technology with a new-type rotary waste incinerator

The technology of steady combustion in a new type of rotary incinerator is firstly discussed. The formation and control of HCl,NOx and SO_(2) during the incineration of sampled municipal organic solid waste are studied with the incinerator. Results showed that the new model of rotary incinerator can effectively control and reduce the pollutant formations by post combustion.

Short-term effects of organic amendments on soil fertility and root growth of rubber trees on Hainan Island, China

Rubber[Hevea brasiliensis(Willd.ex A.Juss.)Müll.Arg.]plantations are the largest cultivated forest type in tropical China.Returning organic materials to the soil will help to maintain the quality and growth of rubber trees.Although many studies have demonstrated that organic waste materials can be used to improve soil fertility and structure to promote root growth,few studies have studied the eff ects of organic amendments on soil fertility and root growth in rubber tree plantations.Here,bagasse,coconut husk or biochar were applied with a chemical fertilizer to test their eff ects on soil properties after 6 months and compared with the eff ects of only the chemical fertilizer.Results showed that the soil organic matter content,total nitrogen,available phosphorus and available potassium after the chemical fertilizer(F)treatment were all signifi cantly lower than after the chemical fertilizer+bagasse(Fba),chemical fertilizer+coconut husk(Fco)or chemical fertilizer+biochar(Fbi)(p<0.05).Soil pH in all organic amendments was higher than in the F treatment,but was only signifi cantly higher in the Fbi treatment.In contrast,soil bulk density in the F treatment was signifi cantly higher than in treatments with the organic amendments(p<0.05).When compared with the F treatment,soil root dry mass increased signifi-cantly by 190%,176%and 33%in Fba,Fco and Fbi treatments,respectively(p<0.05).Similar results were found for root activity,number of root tips,root length,root surface area and root volume.Conclusively,the application of bagasse,coconut husk and biochar increased soil fertility and promoted root growth of rubber trees in the short term.However,bagasse and coconut husk were more eff ective than biochar in improving root growth of rubber trees.

Dynamic test on waste heat recovery system with organic Rankine cycle

Dynamic performance is important to the controlling and monitoring of the organic Rankine cycle(ORC) system so to avoid the occurrence of unwanted conditions. A small scale waste heat recovery system with organic Rankine cycle was constructed and the dynamic behavior was presented. In the dynamic test, the pump was stopped and then started. In addition, there was a step change of the flue gas volume flow rate and the converter frequency of multistage pump, respectively. The results indicate that the working fluid flow rate has the shortest response time, followed by the expander inlet pressure and the expander inlet temperature.The operation frequency of pump is a key parameter for the ORC system. Due to a step change of pump frequency(39.49-35.24 Hz),the expander efficiency and thermal efficiency drop by 16% and 21% within 2 min, respectively. Besides, the saturated mixture can lead to an increase of the expander rotation speed.

Separation-and-Recovery Technology for Organic Waste Liquid with a High Concentration of Inorganic Particles

The environmentally friendly and resourceful utilization of organic waste liquid is one of the frontiers of environmental engineering. With the increasing demand for chemicals, the problem of organic waste liq- uid with a high concentration of inorganic pollutants in the processing of petroleum, coal, and natural gas is becoming more serious. In this study, the high-speed self-rotation and flipping of particles in a three- dimensional cyclonic turbulent field was examined using a synchronous high-speed camera technique; the self-rotation speed was found to reach 2000-6000 rad.s 1. Based on these findings, a cyclonic gas- stripping method for the removal of organic matter from the pores of particles was invented. A techno- logical process was developed to recover organic matter from waste liquid by cyclonic gas stripping and classifying inorganic particles by means of airflow acceleration classification. A demonstration device was built in Sinopec＇s first ebullated-bed hydro-treatment unit for residual oil. Compared with the T-STAR fixed-bed gas-stripping technology designed in the United States, the maximum liquid-removal effi- ciency of the catalyst particles in this new process is 44.9% greater at the same temperature, and the time required to realize 95% liquid-removal efficiency is decreased from 1956.5 to 8.4 s. In addition, we achieved the classification and reuse of the catalyst particles contained in waste liquid according to their activity. A proposal to use this new technology was put forward regarding the control of organic waste liquid and the classification recovery of inorganic particles in an ebullated-bed hydro-treatment process for residual oil with a processing capacity of 2×106 t.a^1. It is estimated that the use of this new tech- nology will lead to the recovery of 3100 t.a 1 of diesel fuel and 647 t.a^1 of high-activity catalyst; in addi- tion, it will reduce the consumption of fresh catalyst by 518 t.a^1. The direct economic benefits of this process will be as high as 37.28 million CNY per year.

Residual Effects of the Organic Amendments Poultry Litter,Farmyard Manure and Biochar on Soybean Crop

The use of organic wastes, as an alternative to inorganic fertilizer, can be an important strategy for Brazilian and tropical agriculture. Despite the importance, few field studies have been done for evaluating organic amendments on soybean crops in Brazil. The study aimed to evaluate the residual effects of the organic amendments poultry litter, farmyard manure and biochar combined with mineral fertilizer on some agronomic attributes of a soybean crop. A field experiment was carried out in a split-split-plot scheme, with three replicates in a randomized block experimental design. The organic sources (plots) at rates of 0, 3, 6 and 9 Mg·ha-1 (subplots) combined with 0, 100, 200, 300 and 400 kg·ha-1 (sub subplots) of a mineral fertilizer were applied in 2008. In 2009, only the mineral fertilizer was used on the soybean crop. As a?result, all evaluated attributes were influenced by the treatments, except for the number of grains per pod. The application of poultry litter provided the highest yield (3715 kg·ha-1 using 9 Mg·ha-1 of the source). A synergistic effect between organic amendments and mineral fertilizer was observed. It was found the possibility of decrease doses of mineral fertilizers by prior use of organic amendments. The most effective dose combination application is 5.5 Mg·ha-1 of organic amendments associated with 200 kg·ha-1 of mineral fertilizer to provide optimum yield. The use of organic amendments, rich in nutrients, is a technology to sustainably increase the soybean grain yield.

Biocompatible Blends Based on Poly(Vinyl Alcohol)and Solid Organic Waste

This work is aimed at the development of new green composite materials through the incorporation of the solid organic waste(SOW)in a thermoplastic matrix.After being ground,the organic waste was exposed to a sterilization process,though an autoclave cycle,in order to obtain a complete removal of the bacterial activity.The SOW was found to have a high amount of water,about 65-70%,which made uneconomical its further treatment to reduce the water amount.Therefore,a water soluble polymer,poly(vinyl alcohol)(PVA)was chosen in order to produce SOW based blends.However,in order to reduce the viscosity of the PVA/SOW slurry,further amount of water was added.The very low viscosity attained by the water suspension allowed to process the PVA/SOW blends by a pressure-free process,for the production of samples,which were afterwards subjected to physical and mechanical characterization.Flexural tests showed the promising properties of the developed blends.In particular,the relevance of porosity was assessed.Increasing the water amount involved a signification increase of porosity,due to a faster water evaporation during processing.On the other hand,compared to neat PVA,addition of SOW allowed to significantly decrease the porosity of the produced samples.Despite this,the mechanical properties of the PVA/SOW blends were shown to be lower than those of neat PVA processed analogously.