Search

Pesticides such as insecticides, fungicides, and herbicides play an important role in the global agricultural industry as they reduce the occurrence of crop diseases, kill pests, and remove weeds. On the other hand, these pesticides are a double-edged sword because they have both acute effects and chronic adverse effects on human health. The widespread use of pesticides has led to their persistence in soil, water, and agricultural products, thus posing a serious threat to public health. Therefore, the removal and analysis of pesticides are critical to protecting human safety and health. When removing pesticides from the environment, it is imperative to ensure high removal efficiency while preventing secondary pollution to the environment. Because of the low concentrations of pesticide residue in the environment, complex matrix, and large throughput of pesticide residue analysis, a low-cost fast pre-treatment technique that has strong selectivity and an enrichment effect on the target pesticide residue, with little environmental impact, is required. Plant biomass-derived biochar is obtained from wheat straw, corn cob, rice husk, etc. This material has a large specific surface area, high pore capacity, tunable surface functional groups, and good environmental compatibility, which make it an inexpensive and efficient adsorbent. Hence, there is a need to systematically review the knowledge regarding the application of plant-based biochar on pesticide removal and pesticide residue analysis. This paper reviews the application progress of plant biomass-derived biochar in the above mentioned two areas over the last decade. The pesticide removal applications include reducing the mobility of pesticides in soil, eliminating the pollution caused by chiral pesticides, loading pesticide-degrading bacteria, and releasing fertilizers sustainably when removing pesticide. As mentioned above, plant biomass-derived biochar has a large specific surface area, a high number of functional groups on the surface, and good environmental compatibility. Therefore, it can effectively remove pesticides or their metabolites from the environment without causing any secondary pollution. During pre-treatment, plan biomass-derived biochar is used as an adsorbent for dispersive solid-phase extraction, solid-phase microextraction, and magnetic solid-phase extraction to selectively adsorb organophosphorus and triazole pesticides in fruits and vegetables, as well as organochlorine pesticides in the aquatic environment. This paper also introduces the adsorption mechanism of plant biomass-derived biochar, where studies based on computational simulations such as the density functional theory, molecular dynamics simulation, and giant canonical Monte Carlo simulation are carefully discussed. The benefits of adopting computational simulations are also mentioned. Finally, this paper summarizes the advantages and disadvantages of using plant biomass-derived biochar in pesticide removal and pre-treatment, as well as the future research trends in this area.

The solubility of 9 sparingly soluble pesticide active ingredients (PAIs) was predicted in 133 deep eutectic solvents (DESs) based on 7 hydrogen bond acceptors and 19 hydrogen bond donors, using a COSMO-RS model. 13 DESs with superior solubility of water-insoluble PAIs were screened out and verified with experiments. The actual measurement results agree well with the forecasting results. When compared with the solubility in pure water, some PAIs can even be mutually dissolvable with tetraethylammonium chloride: decanoic acid (1:2), tetrabutylammonium chloride: decanoic acid (1:3), and tetrabutylammonium chloride: phenol (1:5), such as butachlor, acetochlor, and metolachlor. IR and 1H NMR spectra suggested that hydrogen bonding between DESs and PAIs molecules played a crucial role in solvation. Crucially, the study indicated that it’s feasible to replace toxic organic solvents with DESs in emulsifiable concentrates formulations. The effects of different concentrations of tetraethylammonium chloride: decanoic acid (1:2) on the growth of wheat seedlings were also explored. The results showed that it did not affect the germination rate of wheat seeds, but with the increase of concentration, the growth indexes such as the lengths of shoots and roots grew shorter, the fresh weight of aboveground and underground decreased. This study not only provides COSMO-RS as a useful and reliable tool to screen DESs but also highlights that DESs can be an alternative to replace toxic and harmful organic solvents in emulsifiable concentrates (EC) formulations, which provide ideas and a basis for designing new green pesticide formulations.

1-decyl-3-methyl imidazolium bromide ([C10mim][Br]) aqueous solution was studied as an alternative to aromatic compounds of clethodim emulsifiable concentrate (EC). The solubility of clethodim in [C10mim][Br] aqueous solution (1253.19 g·L− 1) has been greatly improved compared with that in pure water (5.45 g·L− 1) when the mass fraction of [C10mim][Br] was 35%. The electrical conductivity, viscosity and average diameter of [C10mim][Br] aqueous solution were measured. The thermodynamic parameters of electrical conductivity indicate that [C10mim][Br] in aqueous solution can spontaneously occur micelle formation and micellization is an entropy-driven process. The result of the average diameter of [C10mim][Br] can proved the presence of the micelle. And a higher fluidity is more suitable for pesticide dissolution, but not too high. After storage stability test, clethodim formulation water-based with [C10mim][Br] aqueous solution was stable under three different temperatures. The result of bioassay of clethodim formulation water-based with [C10mim][Br] aqueous solution indicates that the new formulation has high herbicidal activity (df = 6, F = 5.871, P = 0.001).

The control and removal of pesticide residues from possible pollution source by using improved methods without secondary pollution is essential for reducing its potential hazards to humans. In this work, a method of combining adsorption and degradation for the removal of pesticide residue was investigated based on the biodegradable microporous starch immobilized laccase (LA–MPS). Biosorbent of microporous starch (MPS) were prepared from maize starch by treating with glucoamylase and α -amylase to increase the specific surface area. Then, laccase with natural biological activity was immobilized on the surface of MPS, the prepared LA-MSP was characterized by SEM, FT-IR, activity assay and stability test. Moreover, LA–MPS coupled with mediators were applied to remove two typical triazine herbicides, atrazine and prometryn, in paddy field water sample. The physical action force between the LA–MPS and pesticide molecules resulted in the good adsorption of LA–MPS to the two pesticides. The apparent rate constants of laccase interaction with pesticide molecules were greatly improved by the adsorption process. Compared with natural degradation, the removal efficiency of atrazine and prometryn were increased by 61% in 7 days, which contributed by 43 ∼ 52% of degradation and 10 ∼ 38% of adsorption. These results indicated that the application of LA–MPS prepared by MPS sorbent was a feasible and green approach for the removal of pesticide residues in paddy field water sample.

Mixed ionic liquids (ILs) of 1-butyl-3-methylimidazolium bromide ([C4mim][Br], A) and 1-decyl-3-methylimidazolium bromide ([C10mim][Br], B) were used as solubilizers for six water-insoluble pesticides (i.e., metolachlor, acetamiprid, acetochlor, clethodim, thiamethoxam, and prochloraz). The solubilities of six pesticides were improved by increasing the B content of the mixed ILs. The aggregation behavior of the mixed IL systems was investigated by means of surface tension, conductivity, and fluorescence measurements. Enhancements in solubility were related to the surface activities of the mixed ILs, as indicated by measurements of their surface active and thermodynamic parameters. This work can reduce the cost and toxicity of using ILs, and the data shown in this paper provide valuable information for choosing a proper mixing proportion of suitable ILs for application to agriculture.

In line with the requirements of green chemistry, the preparation of eco-friendly pesticide formulations has become an inevitable development trend. In this work, we explored the feasibility of four new ionic liquids (ILs, [Octyl trimethyl ammonium] anions, anions = proline, valine, leucine, tartaric acid) as environmentally-friendly solvents for pesticide emulsifiable concentrates, and also as alternatives to traditional imidazole-based ILs since they do not contain the imidazole ring and the anions are natural substances. The results showed that the solubility of pesticides (clethodim, metolachlor, acetochlor, prochloraz, thiamethoxam, glyphosate, acetamiprid) in water with 25%w/v ILs was significantly improved, especially for acetamiprid, where the solubility was increased 19-fold, while it only increased about 4 to 5-fold after adding imidazole-based ILs in our previous work. In addition, the solubilization mechanism was explored by many methods and found that the solubilization effect does not completely depend on the critical micelle concentration (CMC) value but has a great relationship with the hydrophilicity of the ILs which may affect the size of micelles and release behavior to pesticides. Finally, 1H NMR was used to investigate the solubilization sites of ILs for glyphosate, and the interaction between pesticides and anions was explored by the quantum chemical method.

Biosorbents prepared with peanut shell and wheat straw were act as supports for the immobilization of Aspergillus laccase, and the redox mediator syringaldehyde (SA) was used to improve laccase-catalyzed degradation of nine pesticide residues, including isoproturon, atrazine, prometryn, mefenacet, penoxsulam, nitenpyram, prochloraz, pyrazosulfuron-ethyl and bensulfuron-methyl. Pesticides in water and soil samples were effectively removed via biosorbent concentration and subsequent immobilized laccase degradation on peanut shell or wheat straw supports. The Langmuir equation and Freundlich equation described the biosorption isotherms of the nine pesticides. Parameters that affect the degradation was also investigated. With concentration of pesticides and SA of 6.0 mg L−1 and 1 mmol L−1, over 54.5% and 65.9% of pesticides were removed in water in 3 days with a biosorbent immobilized laccase dose of 25 g L−1 for peanut shell immobilized laccase and wheat straw immobilized laccase, respectively. In the treatment of pesticide in soil with a biosorbent dose of 50 g (kg soil)−1, with the maximum degradation rates ranged from 20.9 to 92.9% and 14.7–92.0% in 7 days for peanut shell immobilized laccase and wheat straw immobilized laccase, respectively. Therefore, laccase immobilized on biomass materials has a strong potential for the effective removal of pesticide pollutants from water and soil by biosorption coupled with degradation.

Among eight ionic liquids (ILs) examined, 1-n-butyl-4-methyl-pyridinium bromide (BMPyBr, 5) was used in this study as an appropriate alternative to benzene homologs and derivatives to be used in 10 wt% water-insoluble difenoconazole emulsifiable concentrate (EC). Moreover, 10 wt% difenoconazole EC with BMPyBr (5) exhibited the same efficacy as 10 wt% difenoconazole wettable powder (WP) against powdery mildew on cucumbers under field conditions. The results revealed that difenoconazole EC with BMPyBr (5) had excellent stability at 268 K and 327 K after 14 days through high-performance liquid chromatography (HPLC). Therefore, ILs can be considered as promising environment-friendly adjuvants for pesticides that are commercially processed as EC formulation.

Ionic liquids may be considered as "environment-friendly solvents" for sparingly soluble pesticides. In this study, a series of aqueous ionic liquids (ILs) with different cations and different anions was used as environment-friendly alternative to harmful organic solvents sparingly dissolved in soluble pesticides (metolachlor, acetochlor, clethodim, thiamethoxam, and prochloraz). The aggregation behavior of aqueous ILs was investigated through surface tension measurement. Minimum area per IL molecule (Amin) values from the surface tension measurement showed that alkyl chain length and the halide anions strongly affect the aggregation behavior of ILs and the solubilization of pesticides. The solubility of metolachlor, acetochlor, clethodim, thiamethoxam, nitenpyram, and prochloraz in aqueous ILs increased. More importantly, the solubility of prochloraz in [C10mim][I] became 5771-fold higher than that in pure water. The substantially enhanced solubility of the above pesticides proved that aqueous ILs are promising environment-friendly solvents for pesticides that are commercially processed in emulsifiable concentrate (EC) formulation.

Two triphenylphosphine analogs, (4- tert -butylphenyl)diphenylphosphine ( 1 ) and bis-(4- tert -butylphenyl)phenylphosphine ( 2 ), have been synthesized for the preparation of Rh–P complexes with a formula of Rh(CO)Cl( L ) 2 ( L stands for the ligands 1 and 2 , respectively). Such Rh–P complexes were then attached to amino-group functionalized MCM-41 and MCM-48 for the hydroformylation of 1-hexene in the liquid phase. The supports and the heterogeneous catalysts were characterized by means of XRD, nitrogen adsorption–desorption, FT-IR, HRTEM and AAS. The heterogenized catalysts showed catalytic activity and normal heptanal selectivity comparable to the corresponding homogeneous ones; the advantage in the product selectivity towards the normal heptanal due to the larger cone angle of the ligands over Rh–PPh 3 in the homogeneous systems was also observed in the heterogeneous ones. Considerable interactions occurred between the surface amino-groups and the active rhodium species during the immobilization, resulting in highly dispersed active Rh-moieties and a significant modification in the catalytic stability.