Optimal Weight Ratio Research Articles

Crystalline and Hairy Nanocelluloses for 3D Printed Hydrogels and Strongly Structured Cryogels

This work addresses two main challenges in additive manufacturing of cellulosic hydrogels and cryogels. They are (1) the rheological properties of suspensions of electrosterically stabilized nanocrystalline cellulose (ENCC, a member of the family of hairy nanocelluloses) are inadequate for 3D printing of hydrogels and (2) 3D printed cellulose nanocrystal (CNC) cryogels have poor mechanical properties. The above limitations are effectively addressed by hybridization of CNC/ENCC in the presence of a salt at an optimized weight ratio. Controlling the CNC/ENCC weight ratio leads to high tunability of the rheological properties of the hybrid systems, resulting in high-fidelity printing of 3D hydrogels. Similarly, high tunability in the mechanical performance of the cryogels, obtained upon freeze drying of the printed hydrogels, is achieved by manipulating the CNC/ENCC ratio. Compared to neat CNC cryogels, the compressive strength of the CNC/ENCC (1:1) cryogels is 78% higher. Combined, CNC bestows high printability on the cryogels, while the presence of ENCC leads to the strengthening of the corresponding super porous solid materials. Our findings open new opportunities for sustainable, biocompatible, and lightweight cellulosic structured scaffolds that can be tailored for a broad spectrum of applications.

Smart wearable triboelectric nanogenerator for self-powered bioelectronics and therapeutics

With the development of Triboelectric Nanogenerators (TENGs), the field of energy harvesting has experienced a new era of revolution following the trend to configure innovative materials, design, integrated sensing and high triboelectric output. Here, we investigated the electricity-generation process of TENG by conducting its finite-element analysis using COMSOL Multiphysics software. Further, the effect of different weight concentrations (0%, 2%, 4%, 6%) of multi-walled carbon nanotubes (MWCNT) into the Polydimethylsiloxane (PDMS) matrix was investigated. It has enabled us to find the optimal weight ratio of MWCNT and increase surface charge density, thereby enhancing triboelectric performance for realising smart wearable triboelectric nanogenerators (SW-TENG). On the other hand, a novel dynamic test platform was developed for automated tapping on TENG for quantified performance analysis of SW-TENG. The results indicate that 4 wt% is the optimal weight ratio for fabrication of MWCNT-PDMS based TENG as it recorded the highest open circuit voltage of 195.4 V revealing ∼79% enhancement in triboelectric output as compared to pure PDMS based TENG. Furthermore, SW-TENG was integrated with a bridge rectifier and 10 μF capacitor in order to power bioelectric devices such as a digital thermometer and a pulse sensor. Besides serving as a power source, the SW-TENG shows innovative sensing capabilities for delivering self-powered rehabilitation therapy augmenting the next generation healthcare systems.

Physical Properties of Pulp and Paper: A Comparison of Forming Procedures

Abstract In this work, we used the conventional wet papermaking process and the solution casting procedure to make paper sheets and optimized the relative content of eucalyptus and Simao pine pulps using the mechanical properties of the paper sheet as the evaluation index. The chemical composition, water retention value, zeta potential, carboxyl content, and drainage behavior of the pulp created using the optimal mass ratio for each method were measured, and the resulting paper sheets were characterized via Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption isotherms. We found that for a ratio of eucalyptus to Simao pine pulps of 94:6 using the wet papermaking process, the mechanical properties of sheets took their optimal values, and the tear, tensile, and burst indexes and the folding endurance were equal to 4.43 mN·m2·g−1, 27.47 N·m·g−1, 1.13 kPa·m2·g−1, and 11.38 times, respectively, whereas the ratio leading to the best possible mechanical performance in the solution casting process was 88:12, and the corresponding paper sheets had tear, tensile, and burst indexes and the folding endurance of 11.73 mN·m2·g−1, 23.03 N·m·g−1, 0.68 kPa·m2·g−1, and 25.50 times, respectively. The cellulose, hemicellulose, and lignin contents of the pulp treated by the solution casting method were lower by 1.88, 3.11, and 2.67 percent, respectively, compared to that obtained via the wet papermaking process. However, the water retention value, zeta potential, and carboxyl content of the pulp obtained via solution casting were higher by 50.31, 123.41, and 50.15, percent, respectively, compared to that obtained via the wet papermaking process. The drainage time obtained via the solution casting method was one-fifth of that obtained via the wet forming process. The paper sheet prepared via the solution casting method was found to exhibit weaker hydrogen bonding, a decreased level of crystallinity (26.64% lower), and an increased compactness and N2 gas adsorption capacity (19.55% and 66.7% higher, respectively) compared to the sheet obtained via the wet papermaking process. This work shows that the physical properties of the paper prepared via the two processes considered here, using their respective optimal weight ratios of the different types of pulp, have their own advantages.

Effect of quinacridone content on the performance of graphene/epoxy coatings

AbstractIn this article, long‐lasting anti‐corrosion graphene/epoxy coatings were successfully prepared using quinacridone as dispersant by solution mixing method. The results showed that quinacridone and graphene can form π–π bonds and improve the dispersibility of each other in epoxy coatings. Mechanical and anti‐corrosion properties of epoxy coatings with different contents of quinacridone and graphene have been tested, the results showed that the optimum weight ratio of graphene to quinacridone was 2:5. The tensile strength of the epoxy coatings with 0.2 wt% graphene and 0.5 wt% quinacridone reached 8.12 MPa, which was 1.44 times of the pure epoxy coatings. Moreover, the impedance modulus of the coatings reinforced with quinacridone and graphene was greater than 1011 Ω·cm2 after being immersed in 3.5 wt% NaCl solution for 140 days, which was two orders of magnitude higher than that of the pure epoxy coatings. We found that the reason for the improved performance of the epoxy coatings was not only that quinacridone improved the dispersibility of graphene in the coatings, but also more importantly, quinacridone adsorbed on the surface of graphene to form scale‐like crystalline structures, which enables graphene to reduce folds and wrinkles, thus giving full play to the shielding effect of graphene against corrosion factors.

Risk Dependence and Risk Spillovers Effect from Crude Oil on the Chinese Stock Market and Gold Market: Implications on Portfolio Management

We analyze crude oil’s dependence and the risk spillover effect on the Chinese stock market and the gold market. We compare both static and dynamic copula functions and calculate the average upward and downward spillover effect using the time-varying Copula model and the conditional value-at-risk approach. By utilizing daily data on crude oil prices, China’s stock market, and the gold market, we observe an asymmetric spillover effect: the downside spillover effects from crude oil prices on the Chinese stock market and gold market are larger than the upside spillover effect. We then identify changes in the structure of the sample periods and calculate the dynamic conditional correlation between them. In addition, we explore the optimal weight and hedge ratios in diversified portfolios to mitigate potential risks. Our results suggest that investors and portfolio managers should frequently adjust their portfolio strategies, particularly during extreme events like COVID-19, when financial assets become more volatile. Furthermore, crude oil can help reduce the risk in the Chinese stock market and gold market to some extent during different sub-periods.

A Study of the Effectiveness of Tin on the Thermal Conductivity Coefficient and Electrical Resistance of Se60Te40-xSnx Chalcogenide Glass

This research calculated the effect of partial replacement of Trillium with tin by weight ratios x=0, 5, 10, 15, and 20 of the weight of manufactured samples on the thermal conductivity coefficient of Se60Te40-xSnx chalcogenide glasses. The thermal conductivity coefficient of the samples was calculated using a disk- Lee. The results showed that increasing the concentration of tin improves the thermal insulation ability by decreasing the thermal conductivity value and then determining the optimal weight ratios at which a large thermal insulation is obtained. The electrical resistivity as a function of temperature was studied. The electrical resistivity (rd.c) was calculated as a function of temperature for all samples, using two-point probe techniques in the dark electrical resistivity measurements of Se60Te40-xSnx glasses for all values made in the temperature range 303-455 K. The electrical resistivity was found that it depends on the change in Tin addition, the temperature is clearly affected by the increase in the concentration of tin in the alloy. The electrical resistance increases when the concentration of Tin increase of Se60Te40-xSnx

Formation mechanism and stability of low environment-sensitive ternary nanoparticles based on zein-pea protein-pectin for astaxanthin delivery

This study was devoted for preparing zein-pea protein-pectin ternary nanoparticles through an alcohol-free pH-shifting method for the delivery of astaxanthin (Ax). The complexation of zein and pea protein (PP) in the weight ratio range of 1:2.5 to 1.2:1 maintained the dispersity at pH 7.0 with the average particle size of 90.47–132.38 nm and the polydispersity index of 0.204–0.245. The circular dichroism, fluorescence, Fourier transform infrared spectroscopy and other analyses indicated that the zein interacted with PP to form a composite structure through the folding action of protein structure in the process of pH reduction driven by hydrophobic and electrostatic forces. The incorporation of pectin (pec) further enhanced the physicochemical stability of the nanoparticles. The optimal weight ratio of zein/PP/pec was 2:4:3, and the encapsulation efficiency of astaxanthin reached 94.22%. The X-ray diffraction results showed that the astaxanthin was amorphous after embedding. Compared with Ax/zein-PP, the Ax/zein-PP-pec showed better colloidal stability under the conditions of wide pH range (4.0–8.0), high temperature (90 °C), long time ultraviolet light treatment, and 15-day storage. These results indicated that the construction of the zein-PP-pec nanoparticles could be used as a low environment-sensitive nanocarrier for the loading, protection, and delivery of hydrophobic functional substances such as astaxanthin.

Nipa palm shell as a sustainable precursor for synthesizing high-performance activated carbon: Characterization and application for Hg2+ adsorption

We used for the first time nipa palm shell (NPS) waste as a renewable precursor to synthesize high-porous activated carbon (AC) via direct NaOH activation and investigated its Hg2+ adsorption properties. The characterization results exhibit the successful conversion of NPS into AC with the optimum impregnation weight ratio of NaOH to NPS of 0.5:1, resulting in a large surface area, pore volume, microporosity, and zeta potential of 1214 m2/g, 0.758 cm3/g, 86.4%, and −39.4 mV, respectively. The adsorptive performance of AC towards Hg2+ at 25 °C in a continuous mode was evaluated. High surface area, strongly negative surface charge, and oxygen-containing functional groups of the optimized AC presented a high Hg2+ adsorption capacity (227.86 mg/g). Element composition analysis confirmed the Hg2+ adsorption onto the AC layer. The findings denote the utility and effectiveness of NPS-based AC due to its favorable functional properties and cationic Hg2+ uptake in aqueous media.

Non-enzymatic amperometric glucose sensing on CuO/mesoporous TiO2 modified glassy carbon electrode.

The present study illustrates the fabrication of a glucose sensing electrode based upon binary composite of copper oxide and mesoporous titanium dioxide on glassy carbon (CuO/TiO2/GCE). The X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis evidently showed the phase pure monoclinic CuO nanoparticles and anatase TiO2. N2 adsorption-desorption analysis verified the mesoporosity in TiO2 with specific surface area greater than 105 m2 g-1. Electrochemical impedance spectroscopic analysis proved the remarkable decrease in the charge transfer resistance and facilitation of electron transfer process on the fabricated electrode. The optimum weight ratio of CuO to TiO2 was 1 : 1, and the optimum potential was 0.6 V vs. saturated calomel electrode. The chronoamperometric measurements displayed a detection limit of 1.9 μM, and sensitivities of 186.67 μA mM-1 cm-2 and 90.53 μA mM-1 cm-2 in two linear ranges of 0.05 to 5.2 mM and 5.2 to 20 mM, respectively. The amperometric analysis further showed good reproducibility, high specificity and outstanding stability of the modified electrode.

Preparation and <i>In Vitro</i> Evaluation of W/O Nanoemulsions for the Skin Permeation of 5-Aminolevulinic Acid

We investigated the skin permeation of 5-aminolevulinic acid (ALA) through Yucatan micropig full-thickness skin by using ALA-loaded W/O nanoemulsions composed of Span/Tween/ethanol (EtOH)/isopropyl palmitate (IPP)/10 wt% aqueous ALA solution. The nanoemulsions were prepared using Span 20/Tween 20 (S20/T20), Span 80/Tween 80 (S80/T80), and Span 20/Tween 80 (S20/T80) mixed surfactant systems. Based on the results of the phase diagram study and hydrodynamic diameter measurement of the nanoemulsions, we decided that the optimal weight ratio of Span/Tween/EtOH/IPP/10 wt% aqueous ALA solution in the nanoemulsion was 0.8/0.2/14/19/1.4. The permeability coefficient of ALA in the S20/T80 system was approximately five times larger than those in the S20/T20 and S80/T80 systems. The high skin permeation of ALA afforded by the ALA-loaded W/O nanoemulsion in the S20/T80 system is attributable to a significant enhancement in the partitioning of ALA to the stratum corneum.

Nanoprecipitation Based Preparation and Physicochemical Characterization of Flavonoid Nanoparticles

Out of different secondary metabolites, flavonoids attract the attention of researchers due to their pharmacological potential and health benefits. But solubility and bioavailability issues severely restrict their use. Development of nanoformulation of flavonoids is one of the solutions to overcome these issues. The purpose of this study was to develop and characterize chrysin (CHR) loaded nanoparticles (CHRNs) by nanoprecipitation technique with Eudragit® and polyvinyl alcohol (PVA) as carriers. Particle size, polydispersity index (PDI), zeta potential, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD) was used to characterize the prepared CHRNs. The present study shows that CHRNs can be fabricated by a nanoprecipitation technique using the optimum weight ratio of CHR: Eudragit: PVA (1: 5: 5). The particle size, PDI, and zeta potential were found to be 238.1 nm, 0.434 and -20.1 mV. According to FTIR, CHR developed intermolecular hydrogen bonds with polymers (carriers). SEM imaging confirmed roughly spherical type particles with size of 100–400 nm. The results from the XRPD of the CHRNs showed that the crystal of the drug might be converted to an amorphous state. The release of the drug from the CHRNs was 85.54% compared with the pure drug at 45.11%.

Facile synthesis and comparative study of the enhanced photocatalytic degradation of two selected dyes by TiO2-g-C3N4 composite.

Photocatalysis is considered a useful technique employed for the dye degradation through solar light, visible or UV light irradiation. In this study, TiO2, g-C3N4, and TiO2-g-C3N4 nanocomposites were successfully synthesized and studied for their ability to degrade Rhodamine B (RhB) and Reactive Orange 16 (RO-16), when exposed to visible light. The analytical techniques including XRD, TEM, SEM, DRS, BET, XPS, and fluorescence spectroscopy were used to explore the characteristics of all the prepared semiconductors. The photocatalytic performance of synthesized materials has been tested against both the selected dyes, and various experimental parameters were studied. The experimental results demonstrate that, in comparison to other fabricated composites, the TiO2-g-C3N4 composite with the optimal weight ratio of g-C3N4 (15 wt%) to TiO2 has shown outstanding degrading efficiency against RhB (89.62%) and RO-16 (97.20%). The degradation experiments were carried out at optimal conditions such as a catalyst load of 0.07g, a dye concentration of 50ppm, and a temperature of 50 ℃ at neutral pH in 90min. In comparison to pure TiO2 and g-C3N4, the TiO2-g-C3N4, a semiconductor, has shown higher degradation efficiency due to its large surface area and decreased electron-hole recombination. The scavenger study gave an idea about the primary active species (-OH radicals), responsible for dye degradation. The reusability of TiO2-g-C3N4 was also examined in order to assess the composite sustainability.

How does economic policy uncertainty drive time–frequency connectedness across commodity and financial markets?

This study provides novel insight to the prior literature on the time–frequency connectedness across commodity and financial markets while considering the effect of economic policy uncertainty (EPU). We utilize DY and BK methods combined with the rolling window technique to examine how the connectedness varies over time and across frequencies. Subsequently, we establish regime-switching models to evaluate the influence of EPU on the connectedness and provide implications under different economic states. Our empirical results unveil robust short-term information, volatility, or risk transmission among commodity and financial markets, as they are the main contributors and receivers of shocks, especially during the crisis. Moreover, we identify EPU as a remarkable driver of the interactions among these markets in static and switching regimes. Finally, the optimal weight and hedge ratio responses to EPU are regime-dependent and EPU is more economically important in determining short-term investment. Our findings present vital implications that all market participants should consider the EPU level and prevailing economic conditions when selecting hedging strategies.

Research on the methods for improving the compressive strength of solid waste-based high-strength autoclaved aerated concrete

Three methods were used to improve the compressive strength of autoclaved aerated concrete (AAC), namely, 1) raw material carbonation modification enhancement, 2) pressurized foam enhancement, and 3) immersion of product in alkali and then enhanced by carbonation curing enhancement. The experimental results showed that the optimal weight ratio of fly ash (FA):carbide slag (CS) was 7:3, that is, the calcium:silicon ratio was 4:5. When the CS amount was 2.5 %, after the raw material was modified by carbonation, the compressive strength of the test block reached the maximum of 4.7 MPa, which was 52 % higher than that of the ordinary test block, and the density increased by 10 %. When the foaming pressure was 1.0 × 103 Pa, the compressive strength of the test block reached 10.4 MPa, which was 236 % higher than that of the ordinary test block, and the density also increased by 34 %. When the carbonation curing time was 6 h after alkali immersing, the compressive strength of the test block was the best, reaching 4.4 MPa, which was 42 % higher than the ordinary test block, and the density increased by 4 %. The use of carbonation modification and alkali immersion carbonation together reduced the compressive strength of the test block. The test block prepared by carbonation modification and pressurized foam had the highest strength, which was 12.3 MPa, and the dry density was 857 kg/m3. The orders of the three methods to increase the compressive strength were pressurized foam > alkali immersion carbonation > carbonation modification. This study realized the coupling of AAC preparation and CO2 utilization.

Bifunctional g-C3N4/carbon nanotubes/WO3 ternary nanohybrids for photocatalytic energy and environmental applications

Ternary nanohybrids based on mesoporous graphitic carbon nitride (g-C3N4) were synthesized and presented for developing stable and efficient Hydrogen (H2) production system. Based on photocatalytic activity, optimization was performed in three different stages to develop carbon nanotubes (CNTs) and WO3 loaded g-C3N4 (CWG-3). Initially, the effect of exfoliation was investigated, and a maximum specific surface area of 100.77 m2/g was achieved. 2D-2D interface between WO3 and g-C3N4 was targeted and achieved, to construct a highly efficient direct Z-scheme heterojunction. Optimized binary composite holds the enhanced activity of about 2.6 folds of H2 generation rates than the thermally exfoliated g-C3N4. Further, CNT loading towards binary composite in an optimized weight ratio enhances the activity by 6.86 folds than the pristine g-C3N4. Notably, optimized ternary nanohybrid generates 15,918 μmol h−1. g−1cat of molecular H2, under natural solar light irradiation with 5 vol% TEOA as a sacrificial agent. Constructive enhancements deliver remarkable H2 production and dye degradation activities. Results evident that, the same system can be useful for pilot-scale energy generation and other photocatalytic applications as well.

Amphiphilic chitosan/carboxymethyl gellan gum composite films enriched with mustard essential oil for mango preservation

In this paper, amphiphilic chitosan and carboxymethyl modified gellan gum were synthesized to develop an active edible fresh-keeping material. The optimal weight ratio of CMCS-g-CA/CMGG was determined as 5:2 through the characterization of Fourier transform infrared (FT-IR), Thermogravimetric analysis (TGA), mechanical and barrier properties of the composite films. In addition, the water vapor permeability and oxygen permeability of CMCS-g-CA/CMGG composite films incorporated with mustard essential oil were all declined, and the antibacterial property of the composite film solutions against E. coli, S. aureus and Bacillus anthracis was distinctly improved with the increase of mustard essential oil (MEO) dosage. Furthermore, the CMCS-g-CA/CMGG + 2.0 μL/mL MEO composite film exhibited an effective preservation on mango fruits during 20 days of storage based on the characterization of surface appearance and quality indexes of fruits. Hence, the multifunctional CMCA-g-CA/CMGG/MEO composite films can be served as a prospective eco-friendly packaging material for fruit preservation.

Waste slag benefits for correction of soil acidity.

The global trend is to find new materials with improved environment friendly. The sustainable development of 2030 AGENDA and Waste Management Legislation sustain the disposal of a large quantity of slag at landfill sites by causing environmental consequences which has drawn attention to the need for its more effective recycling. Heavy industries have been operating in the Galati area for over 30 years and an ecological education is necessary for an efficient management of waste slag. The agricultural land resources are an issue world-wide and through this investigative study we showed that the mixture of blast furnace slag and waste slag dumped in landfill can help remediation of the soil acidity and increasing the crop yield. The chemical, structural and morphological properties of three investigated different slag samples are evaluated for recycling in agriculture. Results indicated that the obtained mixture of the slag waste dumped in landfill and of granulated metallurgical slag shows its usage in saving the affected lands. Therefore, by elemental analysis determined by X-ray fluorescence analytical equipment, the optimum weight ratio for the composition of soil-slag mixture were achieved. The obtained mixture presents a balance between soil pH = 5.2 corresponding to a medium acid soil and slag pH = 12.5 which corresponds as strongly basic character which is beneficial in amelioration process of acidic soils for the improving of soil characteristics.

Peripheral octamethyl-substituted nickel(II)-phthalocyanine-decorated carbon-nanotube electrodes for high-performance all-solid-state flexible symmetric supercapacitors

Construction of advanced electrode materials with unique performance for supercapacitors (SCs) is essential to achieving high implementation in the commercial market. Here, we report a novel peripheral octamethyl-substituted nickel(II) phthalocyanine (NiMe2Pc)-based nanocomposite as the electrode material of all-solid-state SCs. The highly redox-active NiMe2Pc/carboxylated carbon nanotube (CNT-COOH) dendritic nanocomposite provides rapid electron/electrolyte ion-transport pathways and exhibits excellent structural stability, resulting in high-capacity activity and impressive cycling stability. The composite prepared with the optimized weight ratio of NiMe2Pc:CNT-COOH (6:10) showed the highest specific capacitance of 330.5 F g−1 at 0.25 A g−1. The constructed NiMe2Pc/CNT-COOH-based all-solid-state symmetric SC device showed excellent performance with a maximum energy density of 22.8 Wh kg−1 and outstanding cycling stability (111.6% retained after 35,000 cycles). Moreover, flexible carbon cloth significantly enhanced the energy density of the NiMe2Pc/CNT-COOH all-solid-state symmetric device to 52.1 Wh kg−1 with 95.4% capacitance retention after 35,000 cycles, and it could be applied to high-performance flexible electronics applications. These findings provide a novel strategy to design phthalocyanine-based electrode materials for next-generation flexible SC devices.

Humidity-Tolerant Room-Temperature Selective Dual Sensing and Discrimination of NH3 and NO Using a WS2/MWCNT Composite.

Continuous detection of toxic and hazardous gases like nitric oxide (NO) and ammonia (NH3) is needed for environmental management and noninvasive diagnosis of various diseases. However, to the best of our knowledge, dual detection of these two gases has not been previously reported. To address the challenge, we demonstrate the design and fabrication of low-cost NH3 and NO dual gas sensors using tungsten disulfide/multiwall carbon nanotube (WS2/MWCNT) nanocomposites as sensing channels which maintained their performance in a humid environment. The composite-based device has shown successful dual detection at temperatures down to 18 °C and relative humidity of 90%. For 0.1 ppm ammonia, it exhibited a p-type conduction with response and recovery times of 102 and 261 s, respectively; on the other hand, with NO (10 ppb, n-type), these times were 285 and 198 s, respectively. The device with 5 mg MWCNTs possesses a superior selectivity along with a relative response of ≈7% (5 ppb) and ≈5% (0.1 ppm) for NO and NH3, respectively, at 18 °C. The response is less affected by relative humidity, and this is attributed to the presence of MWCNTs that are hydrophobic in nature. Upon simultaneous exposure to NO (5-10 ppb) and NH3 (0.1-5 ppm), the response was dominated by NO, implying clear discrimination to the simultaneous presence of these two gases. We propose a sensing mechanism based on adsorption/desportion and accompanied charge transfer between the adsorbed gas molecules and sensing surface. The results suggest that an optimized weight ratio of WS2 and MWCNTs could govern favorable sensing conditions for a particular gas molecule.

Pomelo biochar as an electron acceptor to modify graphitic carbon nitride for boosting visible-light-driven photocatalytic degradation of tetracycline

In this study, biochar (BC) derived from pomelo was prepared via a high-temperature calcination method to modify the graphitic carbon nitride (g-C 3 N 4 ) to synthesize the BC/g-C 3 N 4 composite for the degradation of the tetracycline (TC) antibiotic under visible light irradiation. The experimental results exhibit that the optimal feeding weight ratio of biochar/urea is 0.03:1 in BC/g-C 3 N 4 composite could show the best photocatalytic activity with the degradation rate of tetracycline is 83% in 100 min irradiation. The improvement of photocatalytic activity is mainly attributed to the following two points: (i) the strong bonding with π-π stacking between BC and g-C 3 N 4 make the photogenerated electrons of light-excited g-C 3 N 4 transfer to BC, quickly and improve the separation efficiency of carriers; (ii) the introduction of BC reduces the distance for photogenerated electrons to migrate to the surface and increases the specific surface area for providing more active sites. This study provides a sustainable, economical and promising method for the synthesis of photocatalytic materials their application to wastewater treatment.