Xml with special symbol on php tag to json

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
            <soapenv:Header/>
            <soapenv:Body>
                <p237:getNewSampleSerialNumsOutput xmlns:p237="http://www.cat.com/sos/2008/07/15/EquipmentService/">
                    <Equipment>
                        <p463:serialNumber xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15">JEE10732</p463:serialNumber>
                        <p463:make xsi:nil="true" xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15"/>
                    </Equipment>
                    <Equipment>
                        <p463:serialNumber xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15">LBX10017</p463:serialNumber>
                        <p463:make xsi:nil="true" xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15"/>
                    </Equipment>
                    <Equipment>
                        <p463:serialNumber xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15">ZAE10029</p463:serialNumber>
                        <p463:make xsi:nil="true" xmlns:p463="http://www.cat.com/dds/Equipment/2008/07/15"/>
                    </Equipment>
                </p237:getNewSampleSerialNumsOutput>
            </soapenv:Body>
        </soapenv:Envelope>

As shown above, the xml obtained by

cannot be returned empty according to the normal simplexml_load_string method because the tag has a special symbol.
but I can get the value normally by removing the: on the tag and attribute.
so I"d like to ask how to filter out the special symbols of tags and attribute names or what methods can be directly converted to json format

Thank you