Biochar Meets Single-Atom: A Catalyst for Efficient Utilization in Environmental Protection Applications and Energy Conversion.

Single-atom catalysts (SACs), combining the advantages of multiphase and homogeneous catalysis, have been increasingly investigated in various catalytic applications. Carbon-based SACs have attracted much attention due to their large specific surface area, high porosity, particular electronic structure, and excellent stability. As a cheap and readily available carbon material, biochar has begun to be used as an alternative to carbon nanotubes, graphene, and other such expensive carbon matrices to prepare SACs. However, a review of biochar-based SACs for environmental pollutant removal and energy conversion and storage is lacking. This review focuses on strategies for synthesizing biochar-based SACs, such as pre-treatment of organisms with metal salts, insertion of metal elements into biochar, or pyrolysis of metal-rich biomass, which are more simplistic ways of synthesizing SACs. Meanwhile, this paper attempts to 1) demonstrate their applications in environmental remediation based on advanced oxidation technology and energy conversion and storage based on electrocatalysis; 2) reveal the catalytic oxidation mechanism in different catalytic systems; 3) discuss the stability of biochar-based SACs; and 4) present the future developments and challenges regarding biochar-based SACs.

Insight into disinfection byproduct formation potential of aged biochar and its effects during chlorination.

Biochar can achieve multiple benefits including solid waste management, polluted water remediation, carbon sequestration, and emission reduction. However, various environmental factors (such as temperature variations and dry-wet alternation) and microbial activity may lead to the fragmentation, dissolution, and oxidation of biochar. These accelerate the dissolution of biochar-derived dissolved organic matter (DOM) and then influence disinfection byproducts formation potential (DBPFP) throughout the water treatment process. In this paper, biochars from six biomass feedstocks with five aging processes were prepared, and the DBPFP of biochar and its derived DOM were first studied systematically. Different aging processes might increase the DBPFP of biochar by increasing DOM content and changing the fraction distribution of DOM derived from biochar. Especially, the DBPFP of biochar increased apparently with the chemical aging process. Coexisting with the environmental concentration of humic acid, even aged biochar showed the potential to reduce DBPFP and integrated toxic risk value of the mixed system. In this study, the DBPFP of biochar-derived DOM during the disinfection process is confirmed, and the results can give information to the selection of biomass feedstocks of biochar and its service life in the water treatment process.

In Situ Grown Single-Atom Cobalt on Polymeric Carbon Nitride with Bidentate Ligand for Efficient Photocatalytic Degradation of Refractory Antibiotics.

Semiconductor photocatalysis is a promising technology to tackle refractory antibiotics contamination in water. Herein, a facile in situ growth strategy is developed to implant single-atom cobalt in polymeric carbon nitride (pCN) via the bidentate ligand for efficient photocatalytic degradation of oxytetracycline (OTC). The atomic characterizations indicate that single-atom cobalt is successfully anchored on pCN by covalently forming the CoO bond and CoN bond, which will strengthen the interaction between single-atom cobalt and pCN. This single-atom cobalt can efficiently expand optical absorption, increase electron density, facilitate charge separation and transfer, and promote OTC degradation. As the optimal sample, Co(1.28%)pCN presents an outstanding apparent rate constant for OTC degradation (0.038 min-1 ) under visible light irradiation, which is about 3.7 times than that of the pristine pCN. The electron spin resonance (ESR) tests and reactive species trapping experiments demonstrate that the 1 O2 , h+ , •O2- , and •OH are responsible for OTC degradation. This work develops a new way to construct single-atom-modified pCN and provides a green and highly efficient strategy for refractory antibiotics removal.

Recent progress in covalent organic framework thin films: fabrications, applications and perspectives.

As a newly emerging class of porous materials, covalent organic frameworks (COFs) have attracted much attention due to their intriguing structural merits (e.g., total organic backbone, tunable porosity and predictable structure). However, the insoluble and unprocessable features of bulk COF powder limit their applications. To overcome these limitations, considerable efforts have been devoted to exploring the fabrication of COF thin films with controllable architectures, which open the door for their novel applications. In this critical review, we aim to provide the recent advances in the fabrication of COF thin films not only supported on substrates but also as free-standing nanosheets via both bottom-up and top-down strategies. The bottom-up strategy involves solvothermal synthesis, interfacial polymerization, room temperature vapor-assisted conversion, and synthesis under continuous flow conditions; whereas, the top-down strategy involves solvent-assisted exfoliation, self-exfoliation, mechanical delamination, and chemical exfoliation. In addition, the applications of COF thin films including energy storage, semiconductor devices, membrane-separation, sensors, and drug delivery are summarized. Finally, to accelerate further research, a personal perspective covering their synthetic strategies, mechanisms and applications is presented.

Biological technologies for the remediation of co-contaminated soil.

Compound contamination in soil, caused by unreasonable waste disposal, has attracted increasing attention on a global scale, particularly since multiple heavy metals and/or organic pollutants are entering natural ecosystem through human activities, causing an enormous threat. The remediation of co-contaminated soil is more complicated and difficult than that of single contamination, due to the disparate remediation pathways utilized for different types of pollutants. Several modern remediation technologies have been developed for the treatment of co-contaminated soil. Biological remediation technologies, as the eco-friendly methods, have received widespread concern due to soil improvement besides remediation. This review summarizes the application of biological technologies, which contains microbial technologies (function microbial remediation and composting or compost addition), biochar, phytoremediation technologies, genetic engineering technologies and biochemical technologies, for the remediation of co-contaminated soil with heavy metals and organic pollutants. Mechanisms of these technologies and their remediation efficiencies are also reviewed. Based on this study, this review also identifies the future research required in this field.

Generation and identification of 1O2 in catalysts/peroxymonosulfate systems for water purification.

Catalysts for peroxymonosulfate (PMS) activation are appealing in the purification of organic wastewater. Singlet oxygen (1O2) is widely recognized as a crucial reactive species for degrading organic contaminants in catalysts/PMS systems due to its adamant resistance to inorganic anions, high selectivity, and broad pH applicability. With the rapid growth of studies on 1O2 in catalysts/PMS systems, it becomes necessary to provide a comprehensive review of its current state. This review highlights recent advancements concerning 1O2 in catalysts/PMS systems, with a primary focus on generation pathways and identification methods. The generation pathways of 1O2 are summarized based on whether (distinguished by the geometric structures of metal species) or not (distinguished by the active sites) the metal element is included in the catalysts. Furthermore, this review thoroughly discusses the influence of metal valence states and metal species with different geometric structures on 1O2 generation. Various potential strategies are explored to regulate the generation of 1O2 from the perspective of catalyst design. Identification methods of 1O2 primarily include electron paramagnetic resonance (EPR), quenching experiments, reaction in D2O solution, and chemical probe tests in catalysts/PMS systems. The principles and applications of these methods are presented comprehensively along with their applicability, possible disagreements, and corresponding solutions. Besides, an identifying procedure on the combination of main identification methods is provided to evaluate the role of 1O2 in catalysts/PMS systems. Lastly, several perspectives for further studies are proposed to facilitate developments of 1O2 in catalysts/PMS systems.

Carbonyl and defect of metal-free char trigger electron transfer and O2- in persulfate activation for Aniline aerofloat degradation.

Residual flotation reagents in mineral processing wastewater can trigger severe ecological threats to the local groundwater if they are discharged without treatment. Metal-free biochar-induced persulfate-advanced oxidation processes (KCBC/PS) were used in this study to elucidate the degradation of aniline aerofloat (AAF) - a typical flotation reagent. In KCBC/PS system, AAF can be removed at low doses of catalyst (KCBC, 0.05 g/L) and oxidant (PS, 0.3 mM) additions with high efficiency. The analysis revealed the dominance of O2•- among the identified reactive oxygen species (ROS), which achieved deeper mineralization for the AAF degradation in the KCBC/PS system. The role of the electron transfer mechanism was equally important; the importance was corroborated by the chemical quenching experiments, electron spin resonance (ESR) detection, probe experiments, and electrochemical analysis. It benefited from the electron transfer mechanism in the KCBC/PS system and exhibited a wide pH adaptation (3.5-11) and high resistance to inorganic anions for real mining wastewater treatment. Combined with theoretical calculations and other analyses, the carbonyl group was deemed to be the active site of the non-radical pathway of biochar, while the site of the conversion of SO4•- to superoxide radicals by biochar activation represented a defect. These findings revealed a synergistic effect of multiple active sites on PS activation in biochar-based materials. Moreover, the intermediate degradation products of AAF from mass spectrometry indicated a possible pathway through the density functional theory (DFT) method, which was effective in reducing the environmental toxicity of pollutants for the first time according to the T.E.S.T software and seed germination experiments. Overall, our study proposed a novel modification strategy for cost-effective and environmentally friendly biochar-based catalysts, while also deepening our understanding of the mechanism of activation of persulfate by metal-free carbon-based materials.

Catalytic removal of attached tetrabromobisphenol A from microplastic surface by biochar activating oxidation and its impact on potential of disinfection by-products formation.

There are numerous studies concerning the impacts of widespread microplastic pollution on the ecological environment, and it shows synergistic effect of microplastics and co-exposed pollutants in risk enhancement. However, the control methods for removing harmful pollutants from microplastic surface to reduce their ecological toxicity has rarely been explored. In this paper, magnetic graphitized biochar as a catalyst is shown to achieve 97% removal of tetrabromobisphenol A (TBBPA) from microplastics by biochar mediated electron transfer. The changes in the surface and structure of microplastics caused by various aging processes affected the pollutant attachment and subsequent removal efficiency. After chlorination, the highest disinfection by-product (DBP) generation potential was observed by the group of microplastics attached with TBBPA. The oxidation system of biochar activating peroxodisulfate (PDS) can not only reduce the kinds of DBPs, but also greatly reduce the total amount of detected DBPs by 76%, as well as reducing the overall toxicity. This paper highlights an overlooked contribution of pollutant attachment to the potential risks of DBP generated from natural microplastics during chlorination process, and provides the underlying insights to guide the design of a biochar-based catalyst from wastes to achieve the removal of TBBPA from microplastics and reduce the risks and hazards of co-contamination.

Phytoremediation plants (ramie) and steel smelting wastes for calcium silicate coated-nZVI/biochar production: Environmental risk assessment and efficient As(V) removal mechanisms.

Arsenic is one of the most common and harmful pollutants in environment throughout the world, especially in aqueous solutions. In this study, two kinds of industrial solid wastes (Oxide scale (OS) and Blast furnace slag (BFS)) and one kind of phytoremediation plant waste (Ramie stalk) were used to prepare an environmentally friendly, low-cost, and efficient calcium silicate coated nano zero-valent iron (nZVI)/biochar composite (BOS) for As(V) adsorption. The potential environmental risks of BOS and their effects on removal of arsenic ions from aqueous media were investigated. The adsorption mechanism was explored and discussed based on XRD, SEM-EDS, XPS, etc. The results suggested that the environmental risk and heavy metals toxicity in BOS by co-pyrolysis were significantly reduced compared to the original materials, and no additional contaminant was observed in the subsequent experiments. Simultaneously, the BOS showed excellent As(V) removal capacity (>99%) and regenerative properties. The As(V) removal mechanisms are mainly ascribed to the complexation and co-precipitation between Fe and As, and the hydrogen bond between CO functional group of BOS and As. The mechanism of enhanced nZVI activity for As(V) removal was revealed. A protective layer of Ca2SiO4 was formed on the surface of nZVI during the co-pyrolysis process to prevent the passivation of nZVI. During the reaction process, the Ca2SiO4 covering the nZVI surface would be continuously detached to expose the fresh surface of nZVI, thus providing more redox activity and adsorption sites. This study provides a new way to treat and recycle industrial steel solid wastes and phytoremediation plant wastes, and the produced calcium silicate coated-nZVI/biochar composite is proposed to be a very promising material for practical remediation of As(V)-contaminated water bodies.

Alfalfa biochar supported Mg-Fe layered double hydroxide as filter media to remove trace metal(loid)s from stormwater.

Polluted stormwater (PSW) treatment is becoming increasingly important because of the existence of multiple pollutants from non-point pollution sources. Alfalfa biochar loaded with Mg/Fe layered double hydroxide (AF-LDH) was successfully synthesized to remove trace metal(loid)s from stormwater. The adsorption kinetics and isotherms of metal(loid)s in a mono-component system and the reusability of the composite materials was investigated in this study. The result showed that the maximum removal efficiency for Pb(II), Cu(II), Zn(II), Cd(II), As(V), and Cr(VI) were 98.98 %, 98.11 %, 97.88 %, 97.71 %, 98.81 %, and 50.89 %, respectively, when added calcined AF-LDH (AF-LDO) composite material to the multi-component solution. The AF-LDH and AF-LDO could efficiently remove trace pollutants (10-100 µg/L) from multi-component solution, especially for AF-LDO, which could completely remove the tested six trace metal(loid)s. Furthermore, Fourier transform infrared spectra and X-ray diffraction characterizations supported the Mg/Fe layered double hydroxide reconstruction. The main mechanisms of Pb(II), Cu(II), Zn(II), and Cd(II) (cationic metals) removal were ion exchange and surface precipitation, whereas As(V) and Cr(VI) (anionic metals) were mainly dislodged through the formation of surface complexation, electrostatic attraction, and interlayer anion exchange, concerning the -OH and -COOH of AF-LDH. Importantly, the results of the column experiment demonstrated that AF-LDO was superior to AF-LDH for anionic metal removal from stormwater. In this study, we synthesized AF-LDH and AF-LDO for trace metal(loid) removal and proposed a new and practical approach for stormwater purification.

Microcystis aeruginosa's exposure to an antagonism of nanoplastics and MWCNTs: The disorders in cellular and metabolic processes.

Nanoplastics and carbon nanotubes (CNTs) is one of the emerging environmental contaminants and a widely used engineering nanomaterial, and their biological toxicity has been frequently studied. However, there has been no research on the combined exposure of these two totally different shape nanoparticles. To explore their potential threat to freshwater ecosystems, Microcystis aeruginosa (M. aeruginosa) was exposed to concentration gradients of polystyrene nanoplastics (Nano-PS) and multi-walled carbon nanotubes (MWCNTs). The physiological analysis and whole-transcriptome sequencing were integrated to certify the cytotoxicity. As the physiological results showed, the low concentration (5 mg/L) of these two nanoparticles showed a stimulation on the growth (6.49%-12.2%) and photosynthesis (0-7.6%), and the coexposure was slightly higher than individuals. However, other concentrations showed inhibitory effect, especially at high concentration (50 mg/L), and all physical signs and electron microscope images showed obvious cytotoxicity. Compared with the individuals, the coexposure showed an antagonistic effect induced by the heterogeneous agglomeration which decreased the surface toxicity and the contact with algae of nanomaterials. Transcriptome results showed that coexposure treatment had the fewest differential genes, and the primary effects embodied in the disturbances of cellular and metabolic processes which were superior to the individuals. In the 50 mg/L Nano-PS, the translation process was significantly disordered, and MWCNTs could disrupted the photosynthesis, multiple metabolism processes, membrane transport, and translation. These findings demonstrated the aquatic toxic mechanism from cellular and metabolic processes of Nano-PS and MWCNTs for M. aeruginosa and provided valuable data for environmental risk assessment of them.

Selective graphene-like metal-free 2D nanomaterials and their composites for photocatalysis.

From the viewpoint of sustainability, graphene-like metal-free 2D nanomaterials (GMFs) hold great potential in different photocatalytic fields due to their distinct structures and properties. Although their lattice structures are highly similar, the properties of these nanomaterials are in vast diversity owing to the uniqueness of particular atomic arrangement, thus giving rise to their multi-faceted functionalities in photocatalytic process. In this review, we summarize the latest progress of GMFs and their hybrid composites in photocatalytic field, including graphene and its derivatives, hexagonal boron nitride (h-BN), graphitic carbon nitride (g-C3N4), black phosphorus (BP) and emerging 2D covalent organic frameworks (COFs). Their unique 2D structure and key photocatalytic properties are firstly briefly introduced. Then a critical discussion on their multiple roles in the activity enhancement of composite photocatalysts is emphasized, which in turn points out the direction of maximizing their functions and guides our efficient construction of hybrid photocatalysts based on above 2D nanomaterials. On this basis, a summary about the hybridization of above 2D metal-free materials is presented, and the merits of 2D/2D hybrid systems are elaborated. Last, we wrap up this review with some summative remarks, covering understanding their own unique strengths and weaknesses by comparison and proposing the major challenges and perspectives in this emerging field.

Application of layered double hydroxide-biochar composites in wastewater treatment: Recent trends, modification strategies, and outlook.

In recent years, layered double hydroxide-biochar (LDH-BC) composites as adsorbents and catalysts for contaminants removal (inorganic anions, heavy metals, and organics) have received increasing attention and became a new research point. It is because of the good chemical stability, abundant surface functional groups, excellent anion exchange ability, and good electronic properties of LDH-BC composites. Hence, we offer an overall review on the developments and processes in the synthesis of LDH-BC composites as adsorbents and catalysts. Special attention is devoted to the strategies for enhancing the properties of LDH-BC composites, including (1) magnetic treatment, (2) acid treatment, (3) alkali treatment, (4) controlling metal ion ratios, (5) LDHs intercalation, and (6) calcination. In addition, further studies are called for LDH-BC composites and potential areas for future application of LDH-BC composites are also proposed.

Potential hazards of biochar: The negative environmental impacts of biochar applications.

Biochar has been widely used as an environmentally friendly material for soil improvement and remediation, water pollution control, greenhouse gas emission reduction, and other purposes because of its characteristics such as a large surface area, porous structure, and abundant surface O-containing functional groups. However, some surface properties (i.e., (i) some surface properties (i.e., organic functional groups and inorganic components), (ii) changes in pH), and (iii) chemical reactions (e.g., aromatic C ring oxidation) that occur between biochar and the application environment may result in the release of harmful components. In this study, biochars with a potential risk to the environment were classified according to their harmful components, surface properties, structure, and particle size, and the potential negative environmental effects of these biochars and the mechanisms inducing these negative effects were reviewed. This article presents a comprehensive overview of the negative environmental impacts of biochar on soil, water, and atmospheric environments. It also summarizes various technical methods of environment-related risk detection and evaluation of biochar application, thereby providing a baseline reference and guiding significance for future biochar selection and toxicity detection, evaluation, and avoidance.

Application of biochar for the remediation of polluted sediments.

Polluted sediments pose potential threats to environmental and human health and challenges to water management. Biochar is a carbon-rich material produced through pyrolysis of biomass waste, which performs well in soil amendment, climate improvement, and water treatment. Unlike soil and aqueous solutions, sediments are both the sink and source of water pollutants. Regarding in-situ sediment remediation, biochar also shows unique advantages in removing or immobilizing inorganic and organic pollutants (OPs). This paper provides a comprehensive review of the current methods of in-situ biochar amendments specific to polluted sediments. Physicochemical properties (pore structure, surface functional groups, pH and surface charge, mineral components) were influenced by the pyrolysis conditions, feedstock types, and modification of biochar. Furthermore, the remediation mechanisms and efficiency of pollutants (heavy metals [HMs] and OPs) vary with the biochar properties. Biochar influences microbial compositions and benthic organisms in sediments. Depending on the location or flow rate of polluted sediments, potential utilization methods of biochar alone or coupled with other materials are discussed. Finally, future practical challenges of biochar as a sediment amendment are addressed. This review provides an overview and outlook for sediment remediation using biochar, which will be valuable for further scientific research and engineering applications.

Effects of hydroxyl, carboxyl, and amino functionalized carbon nanotubes on the functional diversity of microbial community in riverine sediment.

Nowadays, more and more attention is focused on the environmental harm brought by the wide production and use of carbon nanotubes. In this study, the metabolic function of sediment microbial community was investigated after unfunctionalized or functionalized multi-walled carbon nanotubes (MWCNTs) were incorporated. The surface functional groups on the studied functionalized MWCNTs in this work were hydroxyl, carboxyl, and amino, respectively. The metabolic functional diversity was determined by Biolog EcoPlates after one-month exposure to MWCNTs. Incorporating 0.5 wt% amino functionalized MWCNTs significantly decreased the microbial activity and diversity, and all types of MWCNTs caused great inhibition on the microbial metabolism at the dosage of 2.0 wt%. The sediment microbes preferred polymers and amino acids. Principal component and similarity analysis indicated that the microbial carbon metabolism was more affected by the MWCNT dosage compared with the functionalization, and 2.0 wt% amino functionalized MWCNTs made the greatest difference in metabolic function of sediment microbial community. These consequences may help to assess the environmental risks of MWCNTs from the aspect of ecological relevance of sediment microbial community.

Mechanism analysis of heavy metal lead captured by natural-aged microplastics.

In this paper, the mechanism of lead (Pb(II)) captured by natural-aged microplastics in aqueous medium was explored. Compared with pristine microplastics, the natural-aged microplastics were more efficient for adsorbing Pb(II). After treated by hydrochloric acid (HCl) or sodium hydroxide (NaOH), the organic film was damaged and the adsorption efficiency decreased obviously, which proved that the organic film played an important role in Pb(II) capture. The fitting results of the isothermal adsorption model showed that this adsorption process was more in line with Langmuir model than with Freundlich model, and the maximum adsorption amount (13.60 mg/g) could also be obtained from the Langmuir model. Based on the comprehensive analysis of XRD, XPS and FTIR results, it was found that Pb(II) capture by natural-aged microplastics was mainly determined by the oxygen containing functional groups (carboxyl and hydroxyl groups) on the organic film. Besides, the measurement results of Zeta potential and pH effect showed that electrostatic interaction was mainly responsible for the Pb(II) capture process.

Photocatalytic degradation of tetracycline antibiotics using delafossite silver ferrite-based Z-scheme photocatalyst: Pathways and mechanism insight.

Tetracycline (TC), a widely used antibiotic, is easy to enter the aquatic ecosystem through soil erosion, livestock manure and wastewater discharge, resulting in a series of risks. The application of Z-scheme photocatalysts with efficient interface charge separation and transfer has been regard as an effective strategy for antibiotic degradation. Herein, a novel ternary Z-scheme Bi12O17Cl2/Ag/AgFeO2 was successfully synthesized by ultrasound-assisted ethanol reduction of Ag+ on the interface of Bi12O17Cl2 and AgFeO2. The Bi12O17Cl2/Ag/AgFeO2 Z-scheme system exhibited an enhanced photocatalytic degradation capability for TC, which was over 6.5 times and 2.4 times higher than those of AgFeO2 and Bi12O17Cl2/AgFeO2 system, respectively. The photocatalytic process of TC was explored, and the results indicated that an optimum catalyst concentration of 0.5 g L-1 and a primeval pH (without adjustment) favored the degradation process, while the introduction of exogenous anions (CO32-, SO42- and NO3-) and organic matter (HA) supressed the degradation of TC. Simultaneously, the possible pathway for the degradation process of TC was presented based on the liquid chromatography-mass spectrometry (LC-MS) analysis. Active species trapping experiments and ESR spectra revealed the significant contribution of O2- in the TC degradation, and verified the Z-scheme mechanism of the Bi12O17Cl2/Ag/AgFeO2 system.

Refined regulation and nitrogen doping of biochar derived from ramie fiber by deep eutectic solvents (DESs) for catalytic persulfate activation toward non-radical organics degradation and disinfection.

Sulfate radical-based advanced oxidation process (SR-AOPs) has great promise in water treatment, there is thereby a pressing need yet still a significant challenge to rationally design an efficient and green catalyst for heterogeneous catalytic reactions. In this study, deep eutectic solvents (DESs) were prepared and employed to simultaneously achieve structural engineering of fibrils separation and surface modifying of nitrogen doping on biochar derived from filaments biomass (NRBF) of Ramie (Boehmeria nivea (L.) Gaud). The more regular structure and pure carbon with reasonable configuration, and the N doped in hexatomic ring of NRBF were great impetus to improve the catalytic performance for peroxydisulfate (PDS) activation, with 4.5 times higher degradation rate of tetracycline than pristine biochar. The in-depth mechanistic study of PDS activation confirmed that dominated pathway was in transition from original reactive species (1O2) in pristine biochar system to a direct electron-shuttle pathway in NRBF system. Moreover, the non-radical dominated NRBF/PDS system showed good potential for bacteria (Escherichia coli) inactivation in disinfection application. Therefore, this work provides the underlying insights to guide the design of a functional and green biochar converting from Ramie filaments by an environmentally friendly facile protocol to achieve multiple purposes of wastewater decontamination and disinfection.

Can microplastics pose a threat to ocean carbon sequestration?

Global climate change has attracted worldwide attention. The ocean is the largest active carbon pool on the planet and plays an important role in global climate change. However, marine plastic pollution is getting increasingly serious due to the large consumption and mismanagement of global plastics. The impact of marine plastics on ecosystem responsible for the gas exchange and circulation of marine CO2 may cause more greenhouse gas emissions. Consequently, in this paper, threats of marine microplastics to ocean carbon sequestration are discussed. Marine microplastics can 1) affect phytoplankton photosynthesis and growth; 2) have toxic effects on zooplankton and affect their development and reproduction; 3) affect marine biological pump; and 4) affect ocean carbon stock. Phytoplankton and zooplankton are the most important producer and consumer of the ocean. As such, clearly, further research should be needed to explore the potential scale and scope of this impact, and its underlying mechanisms.